RJ 

499 

073 


Journal  of 

Psycho-     H 
Asthenics 


Monograph 
Supplements 


Vol.  1,  No.  2 


June,  1915 


Qualitative  Differences  Be- 
tween Levels  of  Intelligence 
in  Feeble-Minded  Children 

By 

Louise  Ellison  Ordahl,  Ph.  D. 
and  George  Ordahl,  Ph.  D. 


Published  by  Minn. 

Minded  and  Colony  for  Epilf. 
Faribault 


VOL.  1,  No.  2  JUNE,  1915 


Qualitative  Differences  Between  Levels 

L»- — 

of  Intelligence  in  Feeble-Minded 
Children , 


Louise  Ellison  Ordahl,  Ph.  D.  and  George  Ordahl,  Ph.  D. 
VV 


Published  by  Minnesota  School  for  Feeble- Minded 
and  Colony  for  Epileptics,  Faribault 


Press  of 

Minnesota  School  for  Feeble-Minded 

and  Colony  for  Epileptics, 

Faribault. 


QUALITATIVE  DIFFERENCES  BETWEEN  LEVELS  OF 
INTELLIGENCE  IN   FEEBLE-MINDED  CHILDREN 

BY  LOUISE  ELLISON  ORDAHL,  Ph.  D., 
and  GEORGE  ORDAHL,  Ph.  D. 

This  study  was  undertaken  at  Faribault,  Minnesota,  in  the 
psychological  laboratory  of  the  Minnesota  School  for  Feeble- 
Minded  and  Colony  for  Epileptics.  Work  was  begun  June  6, 
1914,  and  experiments  were  abruptly  terminated  October  26,  1914. 
The  problem  was  suggested  by  Dr.  F.  Kuhlmann,  Director  of 
Research,  who  also  rendered  the  authors  valuable  assistance  in 
planning  and  arranging  experiments. 

The  Binet-Simon  scale  is  a  means  of  measuring  degrees  of 
general  intelligence,  but  it  does  not  specifically  reveal  the  quali- 
tative differences  upon  which  the  various  levels  of  intelligence 
depend.  Groups  of  children,  both  normal  and  feeble-minded,  may 
be  graded  into  different  levels  of  intelligence  with  a  considerable 
degree  of  accuracy.  But  the  psychological  qualities  character- 
istic of  each  group,  and  the  consequent  qualitative  differences 
between  each  level  has  not  yet  been  determined. 

In  a  general  way  it  is  quite  apparent  that  the  higher  grades 
differ  widely  from  the  lower  grades  and  it  is  quite  possible  to 
detect  a  considerable  difference  in  the  behavior  of  a  group  of 
children  who  are,  for  example,  mentally  six  years  old  and  another 
group  whose  mentality  is  seven  years,  but  just  what  this  differ- 
ence may  be  psychologically  is  not  apparent.  It  has  therefore 
seemed  worth  while  to  attempt  a  series  of  experiments  calculated 
to  reveal  a  psychological  difference  between  the  subjects  doing 
the  experiments.  Accordingly  this  problem  was  undertaken. 

For  the  purpose  of  this  study  it  would  be  best  to  attempt 
experiments  on  the  simple  mental  processes,  and  in  the  field  al- 
ready laid  out  by  normal  adult  and  child  psychology,  and  to  se- 
lect experiments  for  which  norms  are  already  established  and 
which  at  the  same  time  seem  likely  to  yield  results  with  this  class 


4  ORDAHL 

of  people.  Unfortunately  very  few  exist  which  are  at  the  same 
time  applicable  to  the  feeble-minded.  The  authors  attempted  to 
devise  experiments  which  should  test  the  psychological  processes 
comprehended  within  the  following  rubrics :  Sensory  discrimin- 
ations, attention,  memory,  imagination,  judgment,  and  reason. 
The  individual  experiments  are  designated  as  follows. 

1.  Strength  of  grip,  dynamometer. 

2.  Judgment  of  movement. 

3.  Simple  reaction  to  sound. 

4.  Tapping  tests. 

5.  Attention  span. 

6.  Discrimination  of  grays. 

7.  Judgment  of  forms,  two  dimensions. 

8.  Judgment  of  form. 

9.  Judgment  of  size. 

10.  Judgment  of  form,  three  dimensions. 

11.  Memory  for  geometrical  forms. 

12.  Modified  typewriting. 

13.  Ink  blot  test. 

14.  Drawing  designs  inverted. 

15.  Comprehension  of  complex  directions. 

Thirty  cases  of  typical  feeble-minded  "children"  were  se- 
lected, ranging  between  the  chronological  ages  of  fifteen  and 
thirty-five.  If  it  was  found  that  a  case  was  suffering  from  any 
special  defect  such  as  faulty  vision,  it  was  discarded  and  other 
cases  tried.  However,  all  defects,  if  of  a  minor  degree,  could  not 
thus  be  eliminated  since  a  case  might  be  well  along  in  the  ex- 
periment 'before  the  defect  'became  apparent. 

No  cases  were  taken  whose  chronological  ages  were  under 
fifteen.  A  child  under  this  age  with  a  mentality  of  ten  is  possibly 
quite  different  from  one  of  the  same  mentality  but  chronolog- 
ically older.  If  a  child  is  fifteen  and  grades  ten  or  lower  in  men- 
tality he  is  well  possessed  of  the  feeble-minded  traits  and  com- 
pares favorably  with  one  of  the  same  mental  level  but  chron- 
ologically twenty  or  thirty-five.  If,  however,  the  chronological 
age  is  greater  than  thirty-five  there  is  possibility  of  deterioration 


DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE         5 

having  set  in.     For  this  reason  our  cases  were  limited  to  the 
chronological  ages  of  fifteen  to  thirty-five. 

The  cases  were  taken  from  three  groups  of  children,  whose 
mental  ages  were  six,  eight,  and  ten,  as  determined  by  the  Binet- 
Simon  scale.  Ten  cases  were  selected  from  each  of  these  three 
mental  ages,  five  girls  and  five  boys,  thus  making  an  equal  num- 
ber from  each  sex,  a  total  of  fifteen  boys  and  fifteen  girls.  Sub- 
jects were  taken  who  had  not  more  than  six  months  previous 
to  the  experiments  tested  within  two-fifths  of  a  year  of  the  men- 
tal age.  The  average  chronological  and  mental  ages  for  each 
group  were  as  follows. 

Chronological  Mental 
By  Groups                                                                                    Age  Age 

Mental  six 20.5  6.26 

Mental  eight 22.9  8.20 

Mental  ten    19-5  IO-10 

Chronological  Mental 

By  Sex  Age  Age 

Mental   six — girls    21  0.3 

Mental  six — boys 20  6.2 

Mental  eight— girls 22.5  8.2 

Mental  eight — boys 23.4 

Mental  ten— girls    •  •  •  •         21  9.9 

Mental  ten— boys   i?-3  iai6 

The  chronological  ages  for  the  different  groups  do  not  differ 
greatly.  The  Ten  group  has  the  lowest  chronological  average 
which  may  be  in  its  favor.  However,  it  cannot  be  much  since 
the  difference  is  but  one  year  less  than  the  Six  group,  and  3.4 
years  less  than  the  Eight  group.  Whatever  advantage  this  may 
give  the  Tens  over  the  other  groups  is  offset  by  the  lower  aver- 
age mental  age  which  is  .1  year  less  than  for  the  Bight  group, 
and  .16  less  than  for  the  Six  group.  The  Tens  are  placed  at  a 
further  disadvantage  by  the  fact  that  the  girls  of  this  group 
average  slightly  below  ten  years  mentally,  and  two  have  the 
mental  age  of  9  3-5.  In  each  of  the  other  groups  no  individual 
was  below  the  mental  age  for  the  group.  The  Tens  are  at  a 
further  disadvantage  from  the  fact  that  two  of  its  members 
scored  lower  than  the  Eights  in  many  of  the  tests.  This  was  due 


6  ORDAHL 

in  one  case  to  a  peculiar  disposition  which  prevented  the  subject 
putting  forth  proper  effort,  and  in  the  second  case  to  a  peculiar- 
ity of  vision,  and  a  deficiency  in  the  general  physical  tonus. 

The  Eights  as  a  group  'have  an  advantage  of  the  Tens  in 
two  ways,  first,  a  slightly  higher  mental  average,  and  second, 
there  were  two  of  its  members  who  in  many  of  the  tests  stood 
above  the  highest  Tens.  These  facts  should  be  born  in  mind 
in  reading  the  various  tables  throughout  the  following  pages. 
The  figures  are  given  as  different  groups  scored,  but  for  actual 
group  differences  the  Tens  should  be  slightly  higher  and  the 
Eights  slightly  lower  in  every  case,  thus  making  the  differences 
between  the  groups  Eight  and  Ten  greater  than  is  actually 
shown  by  the  tables. 

Throughout  this  study  the  terms  Six,  Eight  and  Ten,  when 
capitalized,  refer  to,  or  are  abbreviations  for  mental  age  six,  men- 
tal age  eight  and  mental  age  ten.  The  number  of  cases  in  each 
experiment  is  uniformly  thirty,  and  is  therefore  not  recorded  in 
the  tables. 

Experiment  i.     Strength  of  Grip. 

Each  subject  was  tested  for  strength  of  grip  in  right  and  left 
hand.  Three  trials  were  given  on  each  of  three  successive  days. 
Smedley's  Improved  Dynamometer  was  used  and  directions  fol- 
lowed as  given  in  Whipple's  Manual  of  Mental  and  Physical  Tests, 
Vol.  I,  page  100.  The  test  was  given  in  the  presence  of  two 
others  of  the  group.  The  subject  was  handed  the  dynamometer 
after  it  had  been  fitted  to  his  hands,  with  the  following  remarks : 
"John,  here,  has  pulled  most  one  hundred  pounds  on  this  dyna- 
mometer. Let  us  see  what  you  can  do."  This  was  usually  suf- 
ficient stimulus  to  call  forth  considerable  effort,  but  it  is  still 
questionable  if  the  results  record  the  full  capacity  of  the  sub- 
jects, especially  with  the  lower  grades  who  did  not  seem  to  dis- 
tinguish between  grimaces,  contortions,  and  real  muscular  ac- 
tion. Several  trials  were  made  on  a  subject  with  no  others  pres- 
ent. The  great  variability  in  the  results  led  the  author  to  discard 
this  method  since  the  results  varied  so  much  with  different  trials 
that  it  was  evident  only  a  small  effort  was  being  exerted.  With 


the  method  used  the  variations  were  only  a  few  pounds.     The 
average  in  Kg.  for  the  groups  were  as  follows. 

TABLE  I 

Right  band 

bix 25.2 

Eight    

Ten   . 


29.4 
29.7 


Left  band 
22.5 

26.5 
29.2 


TABLE  II 

Girls 


Six  . . 
Eight 
Ten  . 


Boys 


Six  . . 
Eight 
Ten  . 


Right  hand 
23.6 

27.6 
26.2 


Right  hand 
26.8 

31.2 
33-2 


Left   hand 
22.5 

25.0 
25.6 

Left   hand 
22.6 

28.0 
32.8 


In  two  cases  the  left  hand  grip  is  greater  than  the  right. 
One  Six  boy  has  a  record  of  sixteen  kilograms  for  the  right 
hand  and  eighteen  for  the  left  hand ;  one  Eight  girl  has  a  record 
of  25.5  for  the  right  and  26  for  the  left  hand.  The  difference 
between  the  right  and  left  hand  grip  is  not  very  large,  but  it  is 
sufficient  to  show  a  difference,  and  that  the  feeble-minded  is  not 
necessarily  ambidextrous  as  is  sometimes  claimed. 

The  norms  given  by  Smedley  for  i8-year-old  boys  and  girls 
are  as  follows. 

TABLE  III 
Boys  Girls 

Right  hand        Left  hand  Right  hand        Left  hand 

49.28  45-01  27.75  27-66 

Comparison  with  tables  i  and  2  show  that  the  feeble-minded 
fall  considerably  below  the  normal  for  eighteen  year  old  boys 
and  girls.  And  the  difference  is  greater  between  the  feeble- 
minded boys  and  normal  boys  than  is  the  difference  between 
feeble-minded  girls  and  normal  girls. 

Experiment  2.    Judgment  of  Movement. 

As  a  test  of  ability  to  perceive  and  estimate  the  extent  of 


8  ORDAHL 

a  simple  movement,  the  following  experiment  was  performed. 
In  a  meter  stick,  five  holes  large  enough  to  accommodate  a  small 
iron  spike,  were  drilled  at  such  distances  that  the  space  between 
the  hole  in  the  middle  of  the  bar  and  the  inside  edge  of  one  hole 
to  the  right  and  one  to  the  left  was  twenty  centimeters,  and  to 
the  two  extreme  holes  forty  centimeters  to  both  sides.  A  flat 
wooden  slide  about  one  centimeter  wide  was  made  to  lie  flat 
across  the  bar  and  slip  easily  along  its  surface  where  the  first 
finger  was  rested  firmly  upon  it,  and  the  arm  moved  to  and  from 
the  body.  The  meter  bar  was  clamped  to  the  side  of  a  low  table 
before  which  sat  the  subject,  and  opposite  him  the  experimenter. 
The  whole  operation  was  concealed  from  the  subject  by  means 
of  a  cardboard  screen  placed  horizontally  between  his  hands  and 
eyes.  The  instructions  given  were:  "Place  your  first  finger  on 
the  little  wooden  slide,  move  away  from  you  when  I  say  'down' 
until  you  hit  against  the  peg.  When  I  say  'back'  move  back 
until  you  hit  the  nail  right  in  front  of  you.  Move  out  again  on 
'down'  and  so  on.  When  you  have  made  the  movement  three 
times,  I  shall  say  'gone'  and  remove  the  peg;  then  you  are  to 
move  to  where  you  think  you  stopped  before."  The  signal  words 
"down,"  "back"  and  "gone"  were  given  at  a  definite  rate,  one 
every  half  second,  "gone,"  of  course,  being  the  seventh.  After 
a  few  preliminary  trials  to  insure  proper  comprehension  of  the 
instructions,  regular  work  began.  Five  trials  in  each  direction 
and  to  each  of  the  two  distances  from  the  center  constituted  the 
twenty  judgments  comprising  one  day's  work,  and  six  days  a 
complete  set. 

Table  4  gives  in  terms  of  centimeters  the  average  amount 
of  error  for  each  age.  Since  there  is  no  evidence  of  learning 
present,  single  day's  results  are  not  given. 

Av.  Errors 

S        +                 S  D.V.  A.D. 

3.0     2.1      .9    3.0  .8     1.3 

2.6     2.0      .8    2.8  .9     1.0 

1.8        .8      ,9    1.7  .5        .7 

Columns  headed  "+"  show  errors  of  over-estimation ;  " — " 
under-estimation ;  "S"  the  entire  number  of  errors  in  any  one 


20 

40 

TABLE  IV 
R 

L 

+ 

— 

S 

+ 

— 

S 

+ 

-      S 

+ 

_ 

Six    . 

.3.3 

.3 

3.6 

.9 

1.3 

2.4 

2.1 

.8    2.9 

2.1 

.9 

Eight 

.2.5 

.4 

2.9 

1.4 

1.3 

2.7 

2.0 

1.0    3.0 

1.9 

.7 

Ten    . 

.1.0 

.5 

1.5 

.6 

1.3 

1.9 

.8 

.9    1.7 

.9 

A 

DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE         9 

rubric.  Portions  of  the  table  headed  "20"  and  "40"  give  the  re- 
sults for  both  hands  for  the  distances  of  20  and  40  centimeters 
respectively.  Those  headed  "R"  and  "L"  give  the  results  for 
both  distances  for  right  and  left  hands  respectively.  Under 
"average  errors''  stand  the  average  results  for  the  entire  120 
judgments  made  by  each  subject.  Therefore,  column  "S"  under 
"average  errors"  should  be  the  same  as  the  average  of  column  S 
under  20  and  40,  and  the  same  as  the  average  of  columns  under 
R  and  L.  Column  liD.  V."  stands  for  the  average  variation  of 
each  individual's  single  day's  work  from  his  average  for  the  six 
days.  Column  "A.  D."  shows  the  variation  of  one  individual  of 
an  age  group  from  other  members  of  that  group. 

On  the  whole  the  difference  between  the  three  age  levels  is 
almost  insignificant,  the  process  probably  being  too  nearly  on  a 
mechanical  level  to  be  much  affected  by  superiority  or  inferiority 
of  intelligence,  but  wihat  difference  exists,  is  in  favor  of  the 
higher  levels.  The  D.  V.'s  indicate  that  the  Tens  are  steadier 
in  their  work  than  lower  ages,  and  the  A.  D.'s  that  there  is  less 
variation  of  one  member  of  the  group  from  the  others  of  the 
group  than  there  is  with  the  two  lower  mental  ages.  The  most 
interesting  facts  come  out  in  comparing  the  plus  and  minus  er- 
rors, particularly  under  20  and  40.  Under  20,  we  see  that  the 
Sixes  made  a  great  deal  larger  plus  than  minus  error.  The 
Eights  show  quite  a  considerable  plus  error,  while  the  Tens  show 
little  difference  either  in  under-  or  over-estimation.  Thi?  means, 
as  observation  of  the  work  also  showed,  that  the  lower  levels 
exerted  poor  judgment  in  making  too  great  an  innervation  for  the 
distance  they  had  to  cover.  They  swung  back  and  forth  between 
the  pegs  with  a  jar  and  trusted  to  the  pegs  to  confine  their  move- 
ments without  trying  to  estimate  the  movement  they  were  mak- 
ing, or  to  be  guided  by  their  estimation  in  their  final  judgment. 
Hence,  the  impetus  of  this  impulse  carried  them  beyond  their 
former  stopping  place.  In  the  judgment  for  40  centimeters  of 
movement,  more  inhibition  is  to  be  overcome  in  making  the 
larger  movement,  and  therefore  this  tendency  is  not  in  evidence. 
There  is  practically  no  difference  between  the  accuracy  of  the 
two  hands,  as  is  seen  from  results  under  R  and  L.  When  re- 


io  OKDAHL 

duced  to  per  cent,  of  difference  we  have:  Tens,  100;  Eights,  36; 
Sixes,  24.  The  results  seem  to  indicate  that  the  process  here  is 
of  so  simple  and  elementary  a  nature  as  to  have  little  depend- 
ence on  degree  of  intelligence,  and  that  what  difference  exists, 
is  probably  due  to  the  fact  that  higher  levels  comprehend  and 
obey  the  directions  of  the  experiment  more  exactly  than  sub- 
jects of  less  intelligence. 

Experiment  3.  Simple  Reaction  time  to  Sound. 
The  apparatus  used  was  Ewald's  chronoscope  and  reaction 
keys.  The  subject  was  instructed  to  hold  the  lever  down  and 
let  it  fly  upon  hearing  the  click  of  the  metal  hammer.  This  metal 
hammer  made  electric  connections  and  started  the  chronoscope. 
The  release  of  the  lever  broke  the  circuit  and  stopped  the  chron- 
oscope, which  counted  the  vibrations  of  the  vibrator,  vibrating 
at  a  twenty-fifth  of  a  second.  The  subject  seemed  to  find  less 
difficulty  in  letting  the  lever  go  than  in  pressing  it  down.  The 
act  of  holding  the  lever  down  seemed  to  keep  him  in  a  more  fa- 
vorable attitude  for  receiving  the  "ready"  signal  and  reacting 
to  the  sound.  Whereas,  if  he  held  the  lever  tightly  between  the 
fingers  in  preparation  for  the  signal,  attention  was  apt  to 
scatter. 

The  subject  was  seated  behind  a  screen  so  as  to  shut  off 
all  view  of  the  apparatus  and  experimenter,  but  where  the  ex- 
perimenter could  observe  the  position  and  movement  of  the  sub- 
ject. Preliminary  trials  were  given  so  as  to  accustom  the  sub- 
ject to  the  apparatus  and  to  acquaint  him  fully  with  the  object 
of  the  experiment.  In  the  regular  series  20  trials  were  given  each 
day  for  five  successive  days,  or  until  100  reactions  were  taken. 
The  results  for  the  age  groups,  and  for  boys  and  girls  together, 
are  given  in  Table  5. 

TABLE  V 

Mental  Age                                                      Group  average  A.  D. 

Six    4115  .1302 

Eight     2759  .0236 

Ten     2385  .0311 

By  this  table  we  see  that  the  Eights  are  superior  to  the 
Sixes  by  .1356  second,  and  the  Tens  stand  .0374  above  the  Eights. 


DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE        11 

Considering  the  highest  score  as  100  per  cent.,  the  difference  be- 
tween the  mentel  levels  is  indicated  as  follows. 

Tens,  100  per  cent. 

Eights,  85  per  cent. 

Sixes,  28  per  cent. 

For  the  feeble-minded  this  experiment  involves  much  more 
than  simple  voluntary  processes.  For  them,  it  requires  an  act  of 
volition  of  considerable  complexity.  The  Six  finds  it  an  almost 
insurmountable  problem  to  attend  to  one  of  the  two  foci,  viz., 
the  grip  on  the  lever  and  the  hammer  click  about  to  appear.  To 
focus  attention  upon  the  grip  and  at  the  same  time  to  maintain 
an  anticipatory  attitude  in  the  margin  of  consciousness  for  the 
sound  of  the  hammer  is  too  much  for  him,  and  to  associate  two 
images  effectively  is  out  of  the  question.  He  must  attend  as  well 
as  he  can  to  one  stimulus,  forego  any  effectual  anticipatory  im- 
agery and  make  his  association  after  the  second  stimulus  ap- 
pears. This  is  true,  but  in  much  less  degree,  of  the  Eights  and 
Tens.  The  experiment  is  valuable,  however,  in  showing  the 
difference  between  the  various  levels  of  intelligence  in  the  ca- 
pacity for  what  to  normal  adults  is  a  simple  voluntary  process. 

Experiment  4.    Tapping  Test. 

As  a  test  of  sustained  attention  and  voluntary  effort,  a  simple 
tapping  test  was  used.  The  apparatus  consisted  of  a  telegraph 
key  clamped  to  the  table  and  connected  with  an  electric  counter. 
A  bell  was  connected  with  a  pendulum  to  ring  every  five  seconds, 
and  the  experimenter  with  little  difficulty  learned  to  read  and 
record  the  counter  on  the  tap  of  the  bell.  The  subject  was  in- 
structed to  tap  with  the  tip  of  the  thumb  and  first  finger  as  fast 
as  possible,  until  told  to  stop.  The  counter  was  in  his  full  view 
as  he  worked,  to  act  as  a  spur,  and  praise  and  flattery  were  lib- 
erally indulged  in  to  procure  maximum  effort.  The  series  re- 
quired 24  minutes  to  perform,  and  consisted  of  tapping  alternately 
with  the  right  and  left  hand  twice,  for  one  minute  each,  with  an 
interval  of  five  minutes  between  successive  periods  of  tapping. 
Table  6  gives  the  numerical  results  of  the  experiment  for  the  dif- 
ferent mental  ages.  The  figures  give  the  average  number  of  taps 
made  for  each  age  for  each  ten-second  period.  Thus  Six,  column 


12  ORDAHL 

3,  shows  the  average  number  of  taps  made  by  the  Sixes  in  the 
third  ten  seconds.  A.  D.  is  the  average  deviation  of  each  indi- 
vidual of  that  age  from  the  general  average  of  the  group. 

TABLE  VI 

1  23            4  5          6  Av.  A.D. 

Six     42.3  45.0    43.6  42.5  41.7  45.9  43.0  .44 

Eight     44.8  47.8    47.0  46.3  45.8  45.7  46.4  .49 

Ten    54.1  53.7    52.1  51.0  51.6  50.4  51.0  .22 

There  is  some  superiority  of  each  age  over  the  next  lowest 
age,  but  not  as  much  as  might  be  expected  from  the  results  of 
other  experiments.  The  most  interesting  fact  is  the  shape  of 
the  curve  of  a  minute's  work  for  the  three  ages.  The  Sixes  start 
low,  rise  a  little  after  ten  seconds,  and  drop  gradually  until  at 
the  end  of  the  fifth  ten-second  period  they  are  below  their  start- 
ing point,  when  they  spurt  on  the  last  lap  to  their  highest  point. 
This  general  tendency  is  interesting  in  showing  the  inhibition  to 
be  overcome  in  the  initial  warming  up  process,  and  the  quick 
fatigue  in  the  middle  of  the  course.  Yet,  the  possibility  of  the 
sudden  high  rise  at  the  end  shows  that,  though  the  subject  be- 
lieves he  has  been  exerting  himself,  he  has  really  been  loafing 
at  his  task.  The  Eights  start  a  little  higher  than  the  Sixes,  rise 
by  the  end  of  ten  seconds  and  begin  to  descend  slowly  until  the 
close,  when  they  are  still  higher  than  at  first.  Here  is  seen  some 
inhibition  at  the  beginning,  but  a  greater  capacity  for  sustained 
effort  after  speed  is  once  up.  However,  the  great  variation 
among  the  Eights  themselves  makes  any  figures  for  them  of  only 
general  value  here,  for  half  the  Eights  resemble  Tens  in  character 
in  this  work,  and  a  third,  Sixes.  The  curve  for  the  Tens  starts 
highest  and  after  the  second  ten  seconds  gradually  decreases 
until  it  reaches  its  lowest  mark  at  the  end.  The  effort  put  forth 
does  not  allow  them  to  recuperate  at  the  end  for  a  spurt  higher. 

All  subjects  except  one  left-handed  subject  showed  a  higher 
average  with  the  right  hand,  which  of  course,  is  the  most  prac- 
ticed and  the  least  fatigable. 

As  a  means  of  further  studying  the  fatigability  of  the  dif- 
ferent levels,  the  averages  were  computed  for  the  first  two  trials, 
and  the  second  two  trials  separately.  Table  7  gives  the  results. 
Under  I  is  given  the  average  of  the  first  trial  with  both  right 


DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE      13 

and  left  hands;  under  2,  the  second  trial  with  each  hand.  Av. 
gives  the  average  for  girls  and  boys.  The  figures  show  that  the 
second  trials  are  poorer  for  the  Sixes  than  the  first  trial,  while 
for  the  Eights  and  Tens,  they  are  practically  the  same. 

TABLE  VII 

Six  Eight  Ten 

12  12  12 

Average    49.2    43.1  46.9    46.5  50.6    50.6 

This  greater  fatigability  of  the  Sixes  is  partly  due  to  fatigue 
of  attention,  but  probably  for  the  most  part  to  the  fact  that  they 
all  pounded  the  keys  with  great  energy  and  were  physically 
somewhat  fatigued  by  the  time  they  had  finished.  This  ex- 
penditure of  effort  on  their  part  occurred  despite  the  fact  that 
they  were  all  told  frequently  to  tap  easily,  and  were  shown 
how  to  do  so.  It  is  just  this  lack  of  judgment  displayed  here 
that  many  students  of  the  feeble-minded  find  so  characteristic. 
In  terms  of  per  cent,  the  difference  between  the  mental  age  groups 
is :  Tens,  100  per  cent. ;  Eights,  89  per  cent. ;  Sixes,  82  per  cent. 
Experiment  5.  Visual  Attention  Span. 

The  material  used  in  this  experiment  consists  (i)  of  three 
series  of  exposure  cards,  A,  B,  and  C,  the  first  five  of  each  of 
which  are  given  in  Plate  I ;  (2)  sheets  of  paper  containing  twenty 
squares,  each  divided  into  four  smaller  squares  similar  to  the  ex 
posure  cards  but  lacking  the  stub  lines.  The  apparatus  used  for 
exposure  was  Whipple's  Tachistoscope.  Each  series  of  exposure 
cards  contained  twenty  two-inch  squares,  each  divided  into  four 
equal  squares.  Short  stub  lines  one-quarter  inch  long  were  dis- 
tributed variously  around  the  sides  and  corners.  These  lines 
may  be  placed  across  the  corners,  project  from  the  middle  of  the 
sides  at  an  angle  of  ninety  degrees  or  forty-five  degrees;  never 
at  any  other  angle  or  position.  Series  A  has  one  stub  line  in 
each  exposure  card.  Series  B  has  two  stu'b  lines  and  Series  C 
has  three. 

The  subject  was  required  to  observe  the  position  and  angle 
of  the  stub  lines  and  to  insert  them  in  blank  squares  placed  be- 
fore him.  The  exposure  interval  was  sixty  sigma.  The  subject 
was  seated  at  a  distance  of  four  feet  from  the  exposure  window 
with  eyes  approximately  on  a  level  with  the  fixation  point.  The 


ORDAHL 
Plate  I 

/ 

— 

y 

_^ 

- 

2 

2 

2. 

' 

/ 

/ 

\ 

3 

3 

3 

V 

f 

J 

- 

If- 

i 

£ 

^ 

N 

- 

— 

1 

1 

5 

4- 

^ 

' 

X 

1 

S 

DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE      15 

following  directions  were  given  each  subject  before  beginning 
the  experiment:  "Notice  the  short  lines  are  always  across  the 
corners,  in  the  corners,  or,  as  you  see,  at  the  middle  of  the  side 
and  turned  either  straight  or  slanting.  I  am  going  to  drop  some 
of  the  cards  before  the  window.  You  watch  carefully  for  the 
short  lines  so  you  can  remember  where  they  are  and  put  them 
in  the  square  before  you  just  where  they  should  be."  From  five 
to  ten  trial  cards  were  then  exposed  first  for  a  longer  and  then 
for  a  shorter  interval.  As  soon  as  the  subject  seemed  to  com- 
prehend the  problem  and  to  have  adjusted  agreeably  to  the  situ- 
ation, the  regular  series  was  begun.  If,  however,  at  the  end  of 
the  ten  trials  it  appeared  there  was  no  adequate  comprehension, 
the  subject  was  allowed  to  copy  from  the  trial  cards  into  the 
blank  square  until  he  understood  what  was  wanted ;  then  the 
trial  series  was  repeated.  This  last  procedure  was  necessary 
with  all  but  two  of  the  Sixes :  all  but  two  of  the  Eights,  and  all 
the  Tens  adjusted  to  the  experiment  before  the  tenth  trial — 
some  almost  immediately. 

The  score  was  obtained  by  counting  the  number  of  stub 
lines  correctly  placed.  Each  subject  was  put  through  each  se- 
ries once  each  day  for  ten  successive  days.  The  time  required 
for  a  daily  sitting  of  sixty  exposures  varied  between  15  and  20 
minutes.  The  daily  average  number  of  correct  cases  for  the 
different  age  lev~lr  is  shown  in  Table  8. 

TABLE    VIII 

1234            56  7  8  9  10  Av.  A.D. 
SERIES  A 

Six     7      6.7      7.7      8.0      7.2      7.5  7.3  7.3  8.1  9.0  7.5  2.23 

Eight 12.9    12.9    14.1    14.6    14.7    16.1  16.4  16.4  15.7  17.3  15.1  2.6 

Ten    14.0    14.3    16.2    17.4    17.2    16.6  16.6  16.8  17.6  17.7  16.4  2.99 

SERIES  B 

Six     5.9      6.9      6.4      8.1      7.5      8.2  8.9  7.9  6.9  7.0  7.39  2.36 

Eight    13.9    13.7    15.9    19.5    18.2    19.5  20.9  22.4  20.8  23.5  18.1  4.66 

Ten    17.7    18.3    20.0    20.7    20.4    21.0  22.4  22.5  23.9  24.0  21.04  5.34 

SERIES  C 

Six     6.3      5.7      6.0      6.9       7.1      7.7  5.8  5.4  6.8  10.0  6.77  2.35 

Eight    15.3    15.1     16.9    16.6    18.5    18.7  18.4  20.2  19.9  23.9  18.31  5.43 

Ten     17.7    18.8    19.0    22.9    24.4    24.5  24.3  27.1  27.0  26.0  23.17  4.31 

In  series  A  the  Tens  score  an  average  of  1.30  above  the 
Eights.  This  difference  alone  is  not  sufficient  to  indicate  a  real 
superiority,  but  this  low  score  on  the  part  of  the  Tens  is  due  to 


16  ORDAHL 

the  fact  that  they  were  doing  so  well  that  they  could  not  feel 
the  necessity  of  doing  better.  The  Eights'  score  was  slightly 
over  double  that  of  the  Sixes.  The  relation  of  the  three  levels  to 
each  other  stand  as  follows : 

For  Series  A:     Tens,  100  per  cent.;  Eights,  92  per 

cent. ;  Sixes,  45  per  cent. 

For  Series  B:     Tens,  100  per  cent.;  Eights,  84  per 

cent. ;  Sixes,  35  per  cent. 

For  Series  C:     Tens,  100  per  cent.;  Eights,  79  per 

cent. ;  Sixes,  28  per  cent. 

It  will  be  seen  from  the  total  average  column  of  Table  8 
that  the  difference  between  the  achievements  of  the  different 
mental  ages  increases  from  series  A  to  C,  or  with  the  increasing 
difficulty  of  the  series.  In  series  A,  the  Sixes  are  45  per  cent, 
of  the  Tens,  while  the  difference  between  the  Tens  and  Eights 
is  only  8  per  cent.  In  Series  B,  the  Sixes  are  35  per  cent,  of  the 
Tens,  while  the  difference  between  the  Tens  and  Eights  in- 
creases to  16  per  cent.  In  Series  C  the  Sixes  fall  to  28  per  cent, 
of  the  Tens  and  the  difference  between  the  Tens  and  Eights  is 
21  per  cent. 

The  A  series  is  not  a  real  test  for  ages  above  six.  The 
Eights  score  75  per  cent,  and  the  Tens  82  per  cent,  correct 
cases.  If  we  consider  this  score  alone,  it  appears  that  it  is 
difficult  enough,  but  the  experiment  did  not  create  a  sufficient 
demand  for  effort.  It  was  easy  enough  after  a  few  trials  to 
observe  the  correct  position  of  one  stub  line  and  consequently 
there  was  not  sufficient  effort  put  forth  to  prevent  one  from 
slipping  by  occasionally.  On  the  other  hand,  35  per  cent,  of 
the  correct  cases  would  indicate  that  the  test  is  too  difficult  for 
the  Sixes.  But  their  behavior  and  attitude  toward  the  problem 
showed  a  clear  comprehension  and  a  general  endeavor  to  score, 
which  would  at  least  indicate  that  the  A  series  is  a  good  measure 
for  effort  of  attention.  At  the  same  time  it  gives  the  subject  an 
opportunity  to  show  whether  or  not  he  belongs  to  a  higher  level 
of  intelligence.  The  Eights  make  their  highest  score  in  Series 

B.  Likewise  the  learning  curve  is  higher  here  than  in  Series 

C,  indicating  that  C  is  too  difficult,  either  because  they  become 


DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE        17 

discouraged  and  cease  to  exert  maximum  effort,  or  because  the 
effort  to  grasp  three  stub  lines  at  one  exposure  causes  confusion 
of  imagery.  The  Tens  make  their  highest  score  in  Series  C, 
also  their  learning  curve  rises  highest  in  this  series.  There  are 
a  few  cases  in  which  three  stub  lines  are  scored  at  one  exposure, 
but  this  represents  the  maximum  of  effort.  If  a  subject  scored 
three  stu'b  lines  at  one  exposure  the  score  for  the  next  exposure 
immediately  following  was  sure  to  fall  to  one.  and  more  likely 
to  zero. 

In  consideration  of  scores  made  and  peculiarities  of  the 
groups  of  Eight  and  Ten  already  mentioned,  the  norms  for  the 
experiments  should  be  as  follows. 

Sixes  should  score  6  in  five  trials  in  Series  A. 
Eights  should  score  between  15  and  20  in  five  trials 
in  Series  B. 

Eights  should  score  between  15  and  20  in  five  trials 
in  Series  C. 

Tens  should  score  between  20  and  25  in  five  trials  in 
Series  C. 

The  learning  element  in  this  experiment  is  small.  It  is 
hardly  at  all  perceptible  for  Sixes  and  not  large  in  either  of 
the  other  two  levels.  If  comparison  is  made  between  the  average 
for  the  first  five  trials  and  the  average  of  the  second  five  trials 
of  each  series,  the  results  stand,  as  given  in  Table  9. 

TABLE  IX 

Series 

Six    A 

Eight    A 

Ten A 

81x    B 

Eight     B 

Ten    B 

Six    C 

Eight   C 

Ten     C 

In  this  experiment  each  series  was  repeated  ten  times.  In 
Table  9  the  left  hand  column  of  figures  shows  the  average  cor- 
rect score  for  the  first  five  trials  of  the  series.  The  middle  col- 
umn gives  the  average  correct  score  for  the  last  half  or  the  last 


Av.  for 

Av.  for 

Gain  in 

first  half 

second  half 

second  half 

6.10 

7.60 

1.50 

13.84 

16.38 

2.54 

15.82 

17.06 

1.24 

6.76 

7.78 

1.02 

16.22 

21.32 

5.10 

19.42 

22.76 

3.34 

6.40 

7.14 

0.74 

16.48 

20.22 

3.74 

20.56 

25.78 

5.22 

i8  ORDAHL 

five  trials.  The  right  hand  column  gives  the  gain  made  in  the 
last  half  of  each  series.  There  are  only  two  cases  out  of  the 
thirty  who  show  any  drop  at  all  in  the  second  half  and  these 
proved  to  be  of  an  unstable  nervous  temperament.  The  Sixes 
make  very  little  gain  in  any  series.  The  gain  for  the  Eights  in 
Series  B  and  the  gain  for  the  Tens  in  Series  C  is  rather  light, 
but  greater  gain  is  made  by  the  end  of  the  first  half  of  the  series, 
or  by  the  fifth  or  sixth  trial,  so  that  the  gain  is  made  by  holding 
the  score  reached  by  the  end  of  the  first  half. 

In  order  that  the  test  may  be  uniformly  one  of  attention  span, 
each  position  of  the  stub  line  in  Series  A  should  be  as  difficult  as 
another,  and  in  Series  B  and  C,  each  group  of  stub  lines,  or  the 
stub  lines  grouped  in  one  exposure  should  be  as  difficult  of  per- 
ception as  the  group  found  in  any  of  the  other  exposures  of  the 
series.  This  does  not  seem  to  have  been  the  case,  and  it  is  per- 
haps not  possible  to  distribute  the  lines  over  the  field  so  as  to 
make  the  large  squares  of  equal  or  of  a  graduated  difficulty  of 
perception.  In  Series  A,  Nos.  10,  19,  and  20  gave  special  diffi- 
culty, and  there  was  a  general  tendency  to  get  the  lines  of  jthe 
lower  square  into  the  upper  squares.  In  Series  B,  No.  13  was 
easiest,  No.  16  quite  as  difficult  as  any.  In  Series  C,  No.  8  was 
among  the  first  to  be  gotten  correctly.  In  general,  the  lines 
about  the  center  of  the  square  where  distances  were  less,  were 
the  most  confusing.  Two  lines  in  the  same  small  square  close 
together  or  on  the  right  or  left  side  of  the  large  square  pre- 
sented less  difficulty,  also  lines  of  similar  quality.  There  seems 
to  have  been  confusion  when  the  line  of  vision  passed  the  cross 
lines  of  the  large  squares.  This  may  be  due  to  the  tendency  of 
the  eye  to  follow  the  lines  or  simply  to  the  'greater  complexity 
of  the  perceptual  image.  It  would  seem  that  one  large  square 
with  the  stub  lines  distributed  around  the  sides  and  corners 
might  make  a  test  more  nearly  free  from  the  disturbance  of  ex- 
ternal factors.  Something  on  this  order  would  have  the  advan- 
tage of  greater  simplicity,  and  the  stub  lines  could  be  more  easily 
grouped  in  order  of  difficult. 

The  experiment  has  revealed  three  differences  in  the  mental 
levels  chosen,  viz.,  differences  in  comprehension  of  simple  prob- 


DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE        19 

lems,  adjustability,  and  attention  span.  The  first  two  are  not 
measurable  in  mathematical  terms  for  this  experiment  but  can 
be  indicated.  The  Sixes  had  virtually  to  be  put  through  the 
experiment  before  they  could  comprehend  it,  and  they  required 
the  longest  time  to  adjust  even  inadequately  to  the  situation. 
The  Eights  can  comprehend  more  easily,  but  required  concrete 
demonstration,  and  adjusted  more  slowly  than  the  Tens.  The 
Tens  comprehended  from  a  verbal  explanation  and  took  up  the 
proper  attitude  for  work  and  adjusted  most  readily  within  five 
minutes. 

Differences  in  attention  span  are  fairly  represented  in  terms 
of  percentage:  Tens,  100  per  cent.;  Eights,  84  per  cent.;  Sixes, 
45  per  cent. 

Experiment  6.     Discrimination  of  Grays. 

As  a  test  of  sensory  discrimination,  matching  different 
shades  of  gray  was  used.  The  apparatus  consisted  of  a  card  board 
about  12x18  inches,  in  which  were  fifteen  openings  two  inches 
square,  arranged  in  three  rows  of  five  squares  each.  In  each 
square,  except  the  middle  one,  were  pasted  from  one  to  fourteen 
thicknesses  of  white  tissue  paper,  one  thickness  in  the  first 
increasing  by  direct  increment  of  one  up  to  fourteen.  Around  the 
middle  opening  were  arranged  strips  of  cardboard  to  form  a 
casing  in  which  to  slip  small  square  frames.  There  were  four- 
teen of  these  frames  consisting  of  two-inch  square  pieces  of 
white  tissue  paper,  each  frame  holding  thicknesses  varying  from 
one  to  fourteen  pieces  to  correspond  with  the  openings  in  the 
large  card.  The  card  with  the  fifteen  openings  was  pasted  flat 
against  a  ground  glass  window  with  a  north  light,  and  the  sub- 
ject seated  directly  in  front  of  it.  (Of  course  the  light  showing 
through  the  papers  would  produce  the  brightest  gray  in  the 
square  with  one  thickness  of  paper  and  the  darkest  for  the  four- 
teen thicknesses).  A  small  frame  was  then  slipped  into  its  place 
in  the  middle  opening,  and  the  subject  told  to  "point  to  the  gray 
just  like  this  one."  A  constant  irregular  order  was  used  to  in- 
sure procedure  without  knowledge  of  the  subject.  Matching 
each  of  the  fourteen  grays  twice  comprised  one  day's  work,  and 


20  ORDAHL 

three  days,  or  eighty-four  judgments  for  a  subject,  constituted 
a  test. 

All  subjects  comprehended  the  task  readily,  yet  it  was  diffi- 
cult to  get  some  of  the  lower  grades  to  take  the  time  and  pains 
to  really  discriminate.  Then,  again,  three  of  the  Tens  took  so 
much  time  to  make  their  decisions  that  after-images  and  fatigue 
must  have  had  something  to  do  in  affecting  the  value  of  their 
judgment. 

In  scoring  a  judgment,  the  amount  of  error  for  that  judg- 
ment was  estimated  by  the  distance  in  the  scale  of  grays  lying 
between  the  gray  chosen  as  identical  with  the  standard  and  the 
one  actually  identical.  For  example,  if  gray  number  14  was 
shown,  and  the  number  12  pointed  to  as  identical,  the  error  was 
recorded  as  2,  or  if  13  was  chosen  when  10  was  shown,  the  error 
amounted  to  3.  The  average  for  each  day's  trials  was  taken  and 
the  average  for  the  entire  three  days'  work.  Since  there  was  no 
evidence  of  effect  of  practice,  only  the  average  results  are  given, 
which  are  contained  in  Table  10. 

TABLE  X 
Six  Eight  Ten 

2-7  i-5  i-3 

The  errors  for  all  levels  are  surprisingly  few,  though  Sixes 
show  a  score  of  errors  twice  as  large  as  that  of  the  other  ages. 
The  three  levels  would  have  been  more  nearly  equal  but  for 
four  very  careless  Sixes.  In  term  of  relative  percentage  it 
amounts  to,  Tens,  100;  Eight,  98;  Sixes,  80. 

The  following  table  gives  the  average  error  for  each 
particular  gray,  ranging  from  one,  which  stands  for  bright- 
est, to  14,  the  darkest.  Naturally  the  easiest  grays  to  discrim- 
inate in  this  series  are  the  brightest,  and  the  most  difficult  the 
darkest. 

TABLE  XI 

1234  5678  9  10  11  12  13  14 

Six     2.7    2.7    2.3    2.0  2.6    2.2    2.7    2.7  2.8  2.9  2.9  3.0  2.6  3.0 

Eight   0.6    1.1    0.8    1.6  1.8    1.3    0.9    2.2  2.4  1.9  2.3  1.6  0.7  0.4 

Ten     0.2    0.8    0.8    1.2  1.3    1.2    1.6    2.6  1.8  2.2  1.9  1.8  1.1  0.6 

The  Sixes  make  about  the  same  amount  of  error  for  each 


DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE        21 

gray,  showing  that  it  is  not  for  them  so  much  a  matter  of  diffi- 
culty of  discrimination,  as  whether  they  could  attend  closely 
enough  to  compare.  The  Eights  show  more  nearly  the  error 
curve  we  should  expect,  except  in  the  big  drop  in  the  middle 
at  seven.  Here  again  attention  is  the  factor  which  explains,  for 
seven  was  to  the  left  of  the  window  into  which  the  variable 
gray  was  slid,  and  the  one  with  which  it  was  natural  to  compare 
it.  Hence,  fewer  mistakes  were  made  here  than  might  be  ex- 
pected. 

The  experiment,  on  the  whole,  does  not  seem  a  particularly 
good  one  for  detecting  differences  in  mental  levels.  In  fact,  re- 
sults indicate  that  when  an  imbecile  can  be  induced  to  attend, 
his  powers  of  discrimination  are  about  equal  to  those  of  a  moron. 
But  the  fact  that  he  concentrates  perfectly  one  minute  and 
wanders  the  next,  makes  the  results  less  valuable  as  criteria  of 
discriminability  than  of  attentive  capacity. 

Experiment  7.     Judgment  of  Forms. 

It  is  quite  evident  that  feeble-minded  children  and  adults 
have  sensations  not  greatly  different  from  normal  persons  ex- 
cept in  the  time  of  response.  The  difference,  then,  should  lie 
in  what  might  be  termed  the  manipulation  of  mental  elements 
or  mental  imagery.  We  have  attempted  an  experiment  which 
should  test  the  relative  ability  of  the  different  mental  ages  to 
receive,  retain  and  transfer  imagery  from  one  sense  to  another. 

A  number  of  forms  were  cut  from  thick  pasteboard  and 
mounted  on  other  pasteboard  cards  five  inches  square.  The 
subject  was  allowed  to  pass  his  hands  under  a  cloth  screen  and 
to  feel  of  the  form  by  passing  his  fingers  around  the  edges  and 
over  the  top  while  it  was  held  in  a  stationary  position.  After 
this  he  was  required  to  point  out  the  form  just  felt  among 
the  ten  forms  drawn  full  size  on  one  large  card.  The  subject  was 
given  directions  as  follows:  "Put  your  hands  under  this  cloth 
and  feel  of  a  form  there  something  like  this  one,  until  you  are 
sure  you  know  what  it  looks  like,  then  I  will  let  you  see  these 
drawings,  and  you  are  to  point  out  which  one  you  have  just 
felt." 

The  series  was  presented  once  each  day  for  five  successive 


^i  ORDAHL 

days,  one  trial  being  allowed  for  each  form,  or  40  trials  in  all. 
The  results  are  given  in  Table  12. 

TABLE    XII 

Av.  daily  Av.  total 

errors  errors  A.D. 

Six  5.6    6.8    7.1    6.7  6.5  6.54  4.32 

Eight    4.2    3.8    4.9     1.2  1.2  3.07  4.00 

Ten    3.7    1.6    3.4    1.7  1.45  2.37  4.32 

According  to  Table  12  the  average  errors  for  five  trials  is 
not  large  for  Eight  and  Ten.  In  terms  of  per  cent,  the  difference 
between  the  levels  stands  thus :  Tens,  100  per  cent. ;  Eights,  90 
per  cent. ;  Sixes,  45  per  cent.  Following  the  daily  score  from 
left  to  right,  it  will  be  noted  that  learning  is  quite  rapid  for 
Tens  and  Eights.  When  we  add  to  this  the  fact  that  errors  were 
almost  constantly  made  on  three  particular  forms,  the  experi- 
ment does  not  appear  to  have  much  value.  It  may,  however,  be 
a  test  of  superficiality  since  it  would  have  been  quite  possible 
for  the  Eights  and  Tens  to  have  made  an  almost  perfect  record. 
They  were  satisfied  with  approximate  certainty.  The  character- 
istic to  be  content  with  approximate  results  and  to  overlook 
small  but  essential  differences  is  not  so  apparent  in  experiments 
that  at  once  challenge  effort  and  put  the  subject  on  his  mettle. 

Experiment  8.     Judgment  of  Forms,  Two  Dimensions. 

On  account  of  the  relatively  unsatisfactory  results  found  in 
experiment  No.  7,  that  experiment  was  modified  and  another  ex- 
periment attempted.  This  contains  the  same  forms  as  Experi- 
ment No.  7,  but  they  were  rendered  more  difficult  by  cutting 
off  corners  and  thus  changing  their  shape.  The  procedure  was 
further  changed  by  allowing  the  subject  to  observe  the  forms  he 
had  felt  instead  of  the  drawings  of  them.  This  changed  two 
factors  simultaneously  with  the  result  that  we  cannot  ascribe 
difference  in  results  to  either  of  the  two  factors,  more  difficult 
forms,  and  the  observations  of  actual  forms  instead  of  drawings 
of  them.  However,  a  few  forms  were  not  changed  but  remained 
the  same  for  both  experiments,  7  and  8.  Comparison  of  the 
blanks  for  both  experiments  show  only  a  very  slight  improve- 
ment in  Experiment  8  for  forms  not  changed,  while  for  the 
changed  forms,  the  score  immediately  drops  off.  This  would  in- 


DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE        23 

dicate  that  there  is  little  difference  in  observing  actual  forms  or 
drawings  of  the  forms.  However,  there  was  a  greater  interest 
in  choosing  the  correct  forms  from  the  real  forms  than  from 
drawings.  The  results  of  the  experiment  are  given  in  Table  13. 

TABLE  XIII 

Av.  daily  errors  Av. 

12345  errors  A.D. 

Six     8.4    9.2    8.4    8.2    7.9              8.52  4.16 

Bight     5.3    4.2    4.3    4.4    2.8              4.26  5.96 

Ten    3.4    2.7    3.6    2.0    1.6              2.66  4.29 

The  relative  differences  between  the  age  levels  are :  Tens,  100 
per  cent. ;  Eight,  78  per  cent. ;  Sixes,  20  per  cent. 

The  differences  here  in  scores  are  more  marked  than  in 
Experiment  No.  7.  There  is  need  for  greater  attention ;  discrim- 
ination is  finer  and  the  process  of  identification  more  complex. 
And  yet  it  appears  that  the  fundamental  process  is  one  of  trans- 
fer of  touch  and  kinaesthetic  imagery  to  visual  imagery.  It  is 
probable,  however,  that  the  discrimination  is  due  to  practice  in 
alternate  feeling  and  seeing  since  an  expression  of  recognition  is 
made  on  feeling  of  an  object  which  has  been,  just  previously, 
the  focal  point  of  attention.  It  becomes,  therefore,  the  recall 
of  a  visual  image  through  touch  and  the  recognition  of  this  image 
through  vision.  In  feeling  of  an  object  not  yet  seen,  the  image 
is  indefinite  until  it  has  been  seen.  W'hen  the  second  touch- 
motor  experience  takes  place,  the  process  is  simultaneously 
touch-motor-visual. 

The  test  is  not  a  good  one  for  the  Sixes.  The  children  of 
this  level  do  not  have  the  necessary  capacity  for  sustained  con- 
secutive thought.  The  low  score  would  indicate  that  the  Sixes 
are  out  of  court  here.  Chances  are  one  in  ten  for  a  correct  score, 
which  lowers  the  actual  choice  and  renders  the  test  unfit.  Be- 
sides the  attitude  in  rendering  a  choice  indicates  they  were  mak- 
ing a  wild  guess. 

The  problem  is  entirely  within  the  capacity  of  the  Eights 
and  Tens,  but  Experiment  8  is  superior  to  Experiment  7,  since 
it  calls  for  clear  attention  and  finer  discriminations.  The  norms 
for  this  test  should  be  50  per  cent,  correct  for  Eights  and  70 
per  cent,  for  Tens. 


24  ORDAHL 

Experiment  g.  Judgment  of  Sizes,  Two  Dimensions. 
This  experiment  was  designed  for  the  same  general  purpose 
as  seven  and  eight,  and  is  constructed  on  the  same  plan,  except 
that  the  forms  remain  constant  while  the  size  varies.  Four  dif- 
ferent forms  were  used,  the  circle,  rectangle,  triangle  and  square. 
These  sizes  were  made  from  heavy  cardboard  and  mounted  on 
cards  five  inches  square.  The  procedure  was  the  same  as  in 
Experiment  8.  The  dimensions  for  the  forms  are  given  in 
Table  14. 

TABLE  XIV 

Circles  Diameter  Squares  Side  Rectangles  Triangles    Base  Altitude 

1.  1%  In.  1.  1%  in.  1.    1    x2      in.  1.  1%  in.      1% 

2.  2      in.  2.  1%  in.  2.     I%x2^4  in.  2.  2       in.      2 

3.  2%  in.  3.  1%.  in.  3.     iy2x2%  in.  3.  2%  ia.      2% 

4.  2%  in.  4.  2      in.  4.     I%x4      in.  4.  3      in.      3 

5.  2%  in.  5.  2%  in.  5.     I%x3      in.  5.  3%  in.      3% 

The  forms  were  presented  once  each  day  for  five  successive 
days,  thus  making  20  trials  each  day,  or  100  trials  in  all.  Errors 
were  determined  by  counting  the  number  of  places  a  size  was 
removed  from  the  correct  place,  e.  g.,  if  the  subject  judged  No.  i 
to  be  No.  2,  the  error  would  be  one.  If  No.  3  was  judged  to  be 
No.  5,  the  error  would  be  two.  Since  there  are  five  sizes  called 
for  in  each  form,  the  highest  possible  error  for  any  judgment  is 
four,  and  for  the  four  forms  given  at  one  sitting  is  80.  It  would 
therefore  be  possible  for  a  subject  to  score  400  errors  for  the  five 
sittings.  Table  15  shows  the  results  for  this  experiment. 

TABLE  XV 

Av.  daily  errors 

of  all  fcrms  Av.           A.D. 

Six    19.9    21.4    18.3    20.0  19.0            19.9 

Eight    11.8      8.7      8.6      8.3  9.0              9.2            2.0 

Ten     8.7      6.5      6.6      5.1  4.0              6.1            1.5 

This  experiment  is  too  difficult  for  the  mental  Six.  It  was 
quite  evident  that  his  judgments  were  largely  accidental.  How- 
ever, his  error  for  any  one  judgment  is  rarely  over  two,  but  com- 
monly one.  The  Eights  and  Tens  comprehend  the  problem 
readily  and  have  very  definite  feelings  as  to  the  correctness  of 
their  judgment.  However,  in  the  first  trials  there  is  a  feeling  of 
uncertainty,  and  the  subject  will  remark:  "Well,  I  don't  know, 
I  am  guessing."  The  guess,  however,  is  more  often  correct  than 


DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE        25 

otherwise;  so  much  so  that  one  is  inclined  to  infer  that  the 
touch  and  kinaesthetic  image  is  directing  the  choice,  although  it 
has  not  yet  quite  fused  with  the  visual  image.  One  form  was 
about  as  difficult  to  judge  as  another. 

The  differences  between  the  various  ages  are  as  follows: 
Mental  Tens,  100  per  cent. ;  Eights,  77  per  cent. ;  Sixes,  7  per  cent. 

This  test  might  be  a  serial  test  beginning  with  the  six-year 
level  if  a  score  with  error  one  is  considered  normal  for  the  Sixes. 
In  this  case  there  should  be  allowed  no  more  than  10  per  cent, 
of  error  in  going  through  the  four  series  once.  The  Tens  should 
be  able  to  go  through  the  four  series  once  with  no  more  than 
25  per  cent,  of  error,  the  Eights  with  35  per  cent,  of  error. 
Experiment  10.  Judgment  of  Forms,  Three  Dimensions. 

It  seemed  from  the  behavior  of  the  subjects  in  Experiments 
8  and  9  that  discrimination  involving  variation  in  three  dimen- 
sions instead  of  two  might  involve  a  more  complex  mental  pro- 
cess in  the  transfer  of  touch  into  visual  imagery.  Twenty  hard- 
wood blocks  were  cut  out,  ten  with  the  dimensions  2  in.  by  2  in. 
by  2  in  ;  ten  3  in.  by  2  in.  by  I  in.  These  blocks  were  then 
shaped  into  a  series  somewhat  on  the  pattern  of  the  forms  used 
in  Experiment  8.  The  blocks  are  given  in  Plate  II.  It  was  at- 
tempted to  make  these  forms  into  a  series  of  graduated  difficulty 
of  perception,  but  results  show  that  some  represented  much 
greater  difficulty  than  others. 

The  same  procedure  was  followed  in  this  experiment  as 
in  Experiment  9,  except  that  the  blocks  were  held  stationary  by 
two  small  holes  bored  in  each  block  which  fitted  over  two  brads 
driven  into  the  table  just  before  the  subject,  and  the  blocks  were 
placed  in  four  rows  always  in  the  same  order.  The  subject  was 
put  through  the  series  once  each  day  for  five  successive  days. 
The  results  are  given  in  Table  16. 

TABLE    XVI 

Av.  daily  errors 

1            23            45                   Av  A.D 

Six  15.7    15.9    15.5    15.5    15.2  15.56  7.5 

Eight    11-0    10.4      8.1       7.4      5.8              8.44  5.8 

Ten     5.8      4.6      4.6      2.7      2.1              3.06  4.4 

The  above  table  shows  the  same  characteristic  group  differ- 


ORDAHL 
Plate  II 


6 


8 


9 


17 


10 


H 


14 


18 


19 


16 


DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE        27 

ences  as  are  seen  in  Experiments  7  and  8.  The  Sixes  can  dis- 
tinguish very  simple  forms,  but  cannot  proceed  beyond  these. 
The  differences  are:  Tens,  100  per  cent;  Eights,  71  per  cent., 
and  the  Sixes  21.4  per  cent. 

A  few  forms  were  recognized  by  all — the  cube,  the  rectan- 
gle and  the  divided  cubes.  6  and  7,  were  most  often  confused  and 
presented  difficulty  to  all  subjects.  The  Tens  adjust  the  most 
readily,  the  Eights  more  slowly  and  the  Sixes  not  at  all.  The 
experiment  offers  opportunity  to  observe  the  readiness  of  ad- 
justment on  the  part  of  the  subject.  There  are  many  forms  so 
similar  that  they  could  be  distinguished  and  differentiated  only 
through  trial  and  error.  The  psychological  process  is  difficult 
to  determine  since  introspection  is  much  needed  here  for  any- 
thing like  a  correct  interpretation;  but  introspection  is  some 
thing  the  feeble-minded  cannot  furnish.  A  few  illusions  evi- 
dently arise  which  disappear  only  with  direct  comparison.  A 
large  portion  of  the  form  conies  immediately  as  one  passes  the 
fingers  over  the  blocks,  or  shoots  into  form  as  the  fingers  turn 
the  corners  or  measure  the  angles.  But  even  with  this  imme- 
diate flash  into  consciousness  there  remains  a  certain  indefinite- 
ness  to  the  imagery  until  the  object  is  observed  visually.  After 
getting  the  touch  and  kinaesthetic  experience  it  remains  for  the 
subject  to  retain  the  image  against  the  visual  perception  of  many 
forms,  some  similar,  until  the  form  identical  with  his  image  is 
sighted.  The  subjects  differ  apparently  in  two  ways.  One  class 
was  "impressionist"  and  the  other  "rationalist."  The  former 
are  visualists  and  do  not  consciously  turn  over  the  im- 
agery mentally,  but  rely  upon  a  feeling  of  familiarity  to  de- 
termine their  choice  as  they  looked  over  the  field  of  20  blocks. 
The  second  class  would  note  similarities,  but  they  would  fix  upon 
one  essential  difference  and  rely  upon  this  factor  for  the  choice 
of  a  block.  Those  who  pursued  the  latter  method  were  able  sev- 
eral days  after  the  last  trial  had  been  concluded  to  pick  out  the 
form  felt  when  the  blocks  were  piled  miscellaneously  in  a  heap 
on  the  table,  without  a  single  error.  The  "impressionists"  were 
not  able  to  do  this  and  when  asked  to  indicate  how  they  dis- 
tinguished the  forms  one  from  the  other,  could  not  do  so.  Dis- 


38  ORDAHL 

crimination  by  noting  carefully  the  characteristics  of  the  object 
was  common  to  both  Eights  and  Tens.  But  the  Tens  exercised 
more  control  than  did  the  Eights.  The  experiment  calls  for  per- 
ceptions of  relations,  capacity  for  forming  clear-cut  distinctions, 
and  a  certain  small  amount  of  reasoning.  While  it  is  not  an  ab- 
solute certainly,  there  are  certain  strong  indications  that  it  re- 
quires some  mental  effort  to  make  the  transfer  from  a  touch- 
kinaesthetic  imagery  to  visual,  and  that  this  experiment  reveals 
the  process  in  an  elementary  way.  The  experiment  as  a  whole 
was  more  interesting  to  the  subjects  than  Experiment  No.  9, 
and  for  this  reason  is  superior  as  a  mental  test. 

Experiment  u.  Memory  for  Geometrical  Forms. 
As  a  test  of  simple  visual  memory,  ten  cards,  each  contain- 
ing a  geometrical  form  were  used.  Each  form  consisted  of  a  cir- 
cle two  inches  in  diameter,  with  the  diameter  drawn  through  it 
horizontally,  vertically,  or  at  45  degrees  from  either  horizontal  or 
vertical,  one  or  two  one-inch  lines  lying  outside  the  circle  as  tan- 
gents, and  one  or  two  one-inch  tines  lying  inside  as  chords,  there 
being  always  four  such  lines  in  all  to  a  circle,  as  shown  in  Plate 
III,  A.  Since  each  drawing  was  entirely  different,  by  turning  a 
card  in  each  of  the  four  possible  positions,  forty  instead 
of  ten  variations  of  form  were  produced.  The  cards 
were  placed  in  two  parallel  rows  on  a  table  at  which 
the  subject  sat,  the  order  being  a  definitely  planned  ir- 
regular one,  to  avoid  the  factor  of  place  memory.  A 
cloth  curtain  hung  before  the  subject  to  conceal  operations. 
The  subject  was  told,  "I  am  going  to  show  you  a  card  with  a 
drawing  on  it,  study  it,  and  after  ten  seconds  I  shall  take  it 
away,  and  you  must  pull  the  curtain  aside  and  point  to  the  one 
you  have  been  studying."  The  card  was  slipped  under  tfhe  cur- 
tain and  shown  to  him  for  the  ten  seconds,  and  immediately 
put  back  into  place,  when  he  tried  to  pick  it  out  from  the  other 
drawings.  After  the  ten  cards  had  been  exhibited,  they  were 
placed  in  the  second  position,  then  in  the  third  and  fourth,  thus 
making  forty  trials  in  a  day's  work.  Three  days'  work  of  120 
trials  for  each  subject  constituted  a  complete  series. 


DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE         29 


Plate  III 
A  B 


ORDAHL 

After  the  above  experiment  on  immediate  recall,  a  similar 
one  was  used  for  delayed  recall,  the  only  difference  in  method 
being  that  the  subject  waited  ten  seconds  after  having  seen  the 
card  before  he  tried  to  select  it  from  the  others.  Here,  owing  to 
necessity  of  leaving  experimentation  entirely,  only  two  days' 
records  were  taken  and  only  twenty  judgments  on  each  day, 
making  forty  the  total  number. 

In  a  third  experiment  the  delay  was  extended  to  one  min- 
ute. Since  only  ten  judgments  could  be  allowed  here,  the  results 
do  not  bear  a  value  entirely  comparable  with  those  of  the  first 
two  forms  of  the  experiment,  but  the  results  are  given  for  what 
they  are  worth. 

Table  17  gives  the  average  percentage  of  correct  cases  for 
each  age  of  the  three  forms  of  the  experiment. 

TABLE  XVII 

Six 

Eight 

Ten 

There  is  quite  a  distinct  and  remarkable  difference  between 
the  different  age  levels.  The  Sixes  do  practically  nothing,  the 
Eights  get  about  half,  and  the  Tens  more  than  three-fourth. 
The  task  of  discriminating  the  differences  between  the  arrange- 
ment of  meaningless  lines  was  too  complicated  and  difficult  a 
problem  for  the  weak  attentive  capacity  of  the  Sixes.  Memory 
hardly  seemed  a  factor  here,  judging  from  their  careless  manner 
of  studying  the  card  during  its  exposure  and  the  haphazard  way 
in  which  they  made  their  selection  when  it  was  time  to  judge 
what  card  they  had  seen-  The  Eights  were  more  sensible  in 
their  methods,  but  it  is  probable  that  here,  too,  discriminability 
and  attentive  capacity  was  an  important  factor. 

Reduced  to  per  cent,  difference,  the  three  ages  stand : 
Immediate  recall — 
Sixes,  20 
Eights,  72 
Tens,  100 


Immediate 
recall 

16 

10-second 
interval 
2O 

1-tninnte 
interval 
2O 

it  .                                           s6 

cc 

6^ 

77 

DD 
OO 

uo 

8<; 

DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE        31 

Ten  seconds  delay — 

Sixes,  22 

Eights,  60 

Tens,  100 
One  minute  delay — 

Sixes,  23 

Eights,  74 

Tens,  100 

For  the  Tens  only  is  there  any  considerable  difference  be- 
tween the  three  forms  of  recall,  who  profit  by  the  ten  second 
intervals,  and  are  but  a  little  lower  after  one  minute  interval, 
though  higher  than  in  immediate  recall.  Individual  figures  show 
no  learning  for  any  age,  except  for  the  Tens,  and  here  only  a 
very  slight  degree. 

The  experiment  demands  too  great  a  degree  of  attentive  ca- 
pacity for  the  Sixes,  so  that  whatever  value  it  might  have  as 
a  measure  of  retentiveness  is  eliminated.  Perhaps  it  is  even  a 
little  too  difficult  for  the  Eights,  but  for  Tens  it  might  make  a 
good  mental  test,  if  70  per  cent,  or  more  correct  judgments  were 
required,  with  an  improvement  in  the  case  of  delayed  recall. 
Eights  should  be  required  to  get  about  half  the  cases  right  for 
immediate  recall  and  do  at  least  no  worse  in  delayed  recall. 

Experiment  12.     Modified  Typewriter. 

This  was  an  experiment  in  learning  a  connected  series  of 
visual-motor  coordinations.  The  apparatus  used  was  an  ar- 
rangement resembling  in  principle  a  simple  typewriter  of  four 
keys.  On  each  key  was  pasted  a  color,  and  when  any  key  was 
pressed  a  different  color  appeared  just  above  it,  through  a  slot 
in  a  vertical  screen,  which  was  the  color  of  the  next  key  to  be 
struck.  A  red  key  threw  up  yellow  ;  a  yellow,  blue ;  a  blue,  green, 
and  green,  red,  the  last  key  of  the  series  throwing  up  the  color 
of  the  first,  making  an  uninterrupted  process  to  be  continued  un- 
til a  signal  to  stop.  Each  key  was  connected  with  an  electrical 
counter,  so  that  every  stroke  registered  a  count.  A  bell  was  con- 
nected with  a  second  pendulum  to  ring  once  every  minute,  as  a 
signal  for  starting  and  stopping.  The  errors  were  easily  ob- 
served and  recorded  by  the  experimenter.  After  the  principle 


32  ORDAHL 

of  the  apparatus  and  the  task  was  explained  briefly  to  the  sub- 
ject, he  was  allowed  a  few  trials  to  make  sure  that  he  understood. 
Every  subject  was  instructed  to  use  four  fingers,  the  first  and 
middle  fingers  of  both  hands,  and  to  strike  each  color  with  its 
own  particular  finger.  But  the  latter  was  impossible  for  some 
subjects,  and  though  all  were  given  the  same  instructions,  only 
part  of  them  succeeded  in  using  four  fingers.  Ten  one-minute 
trials  a  day  with  a  minute  interval  between  successive  trials  and 
six  days'  work  constituted  a  regular  series.  When  results  in- 
dicated that  the  subject  might  be  able  to  work  without  the  aid 
of  the  visual  cue,  a  cardboard  screen  was  placed  to  conceal  both 
the  colors  on  the  keys  and  the  small  colors  the  keys  showed  on 
being  pressed.  Where  a  subject  could  not  work  without  the  aid 
of  vision  at  the  end  of  six  days  of  practice,  the  series  was  con- 
tinued for  four  more  days.  The  numerical  results  s'how  only  six 
days'  work.  Throughout,  the  subject  was  kept  informed  as  to 
the  score  and  mistakes. 

The  problem  for  the  subject  then  involved  a  series  of 
four  motor  reactions  to  specific  visual  cues.  It  comprised  the 
perception  of  the  color  shown  through  the  slot,  the  perception 
of  the  key  with  the  same  color  pasted  on  it,  the  choice  motor  re- 
action involved  in  the  pressure  of  that  key,  and  the  choice  of 
the  finger  used. 

Table  18  shows  the  results  in  numerical  form  for  the  differ- 
ent mental  ages.  "S"  indicates  the  number  of  strokes  in  a  min- 
ute, "E"  the  number  of  errors,  and  "C"  is  "S"  minus  "E,"  or  the 
correct  strokes.  The  figures  at  the  head  of  the  columns  indicate 
days.  Thus  the  figure  under  Six,  column  6,  "S,"  stands  for  the 
average  strokes  made  by  the  Sixes  on  the  sixth  experimental  day. 
Column  A.  D.  gives  the  average  deviation  of  each  individual 
of  the  group  from  the  average  for  that  group. 


ENCES  BETWEEN  LEVELS  OF  INTELLIGENCE 


33 


TABLE    XVIII 
SIX 

DayS~                                                   1           2  3  4  5  6  Av.      A.D. 

h 27-0      35.2  42.7  48.9  53.3  61.8  45.5 

E 4-3        4.9  4.5  5.2  6.6  7.0  5.8 

C 22.7      30.3  38.2  43.7  46.7  54.8  39.8      21.8 

EIGHT 

S 50.8      81.8  114.3  128.0  138.3  147.4  111.0 

E 5.7        5.7  6.6  9.7  6.1  2.1  5.0 

C 45.1      76.1  107.7  118.3  132.2  145.3  106.1      44.4 

TEN 

S 85.4    151.3  187.5  217.7  246.9  281.8  201.7 

B 4.7        2.9  1.7  1.6  2.8  2.1  2.7 

C-    ••"••• • 8°-7    148.4  185.8  216.1  244.1  279.7  299.0      37.9 

All  ages  show  an  increase  from  day  to  day,  the  sixth  being 
about  twice  that  of  the  first  day's  record.  The  Sixes  start  low- 
est and  increase  at  the  slowest  rate,  the  Tens  start  highest  and 
increase  at  the  fastest  rate,  while  the  Eights  show  a  result  just 
between  the  two.  The  errors  of  the  Sixes  remain  about  constant, 
though  the  number  of  strokes  increases,  showing  an  improve- 
ment in  accuracy;  the  errors  of  the  Tens  decrease,  despite 
the  great  increase  in  strokes,  giving  a  practically  perfect  record 
as  to  accuracy,  while  the  Eights  again  show  a  middle  tendency. 
Though  the  A.  D.  is  large,  it  indicates  rather  a  variation  within 
the  group  than  an  over-lapping  of  the  three  groups. 

Further  interesting  differences  of  the  three  mental  ages  is 
seen  in  the  following  table,  which  gives  the  result  of  each  trial 
for  the  first  days'  work  done  by  the  three  levels. 

TABLE  XIX 

Trials—                        123456789  10 

Six     16.4      17.4      20.2      21.5      21.9      22.3      25.5      27.6      24.3  28.8 

Eight : 29.7      35.1      34.8      42.0      42.8      47.3      48.5      49.1      57.8  61.7 

Tea 47.8      67.6      75.3      87.8      99.4      98.9    108.2    110.4    117.6  120.7 

As  in  the  case  of  the  record  of  the  entire  time,  the  Sixes  start 
very  low,  the  Eights  almost  twice  as  high  as  the  Sixes,  and  the 
Tens  twice  as  high  as  the  Eights,  while  about  the  same  relation- 
ship holds  between  each  of  the  ten  trials. 

In  their  manner  of  working,  the  subjects  fell  into  almost  as 
definite  groups  as  their  numerical  results  show.  All  subjects 
grasped  the  problem  after  some  slight  explanation,  but  the  Sixes 
required  more  instruction  and  more  practice  before  regular  work 
could  be  started.  Using  four  finsers,  one  for  each  key,  seemed  to 


34  ORDAHL 

be  the  most  difficult  task  of  all  and  only  two  of  the  Sixes  suc- 
ceeded in  doing  so,  even  after  the  tenth  day-  Half  of  the  Eights 
managed  it,  with  considerable  difficulty,  but  all  of  the  Tens  were 
using  four  fingers  by  the  end  of  the  second  day's  work.  Of 
course,  this  was  a  more  economical  method  if  it  could  once  be 
acquired  and  resulted  in  a  quicker  mechanization  of  the  process 
and  a  more  rapid  rate  of  work.  For  half  of  the  Eights  and  all 
but  two  of  the  Sixes,  it  was  too  complicated  a  matter  to  distin- 
guish the  proper  one  of  the  four  fingers  and  use  it  when  required, 
and  no  results  would  have  been  possible  had  they  not  been  al- 
lowed to  use  only  the  index  finger  of  each  hand. 

Sixes  with  one  exception  were  careless  in  their  work,  and 
many  times  they  would  push  any  key  which  happened  to  be 
the  easiest,  until  urged  to  be  careful.  Three  of  the  Eights  were 
faulty  in  this  respect,  but  rather  on  account  of  confusion  result- 
ing from  effort  at  high  speed  at  the  expense  of  correctness,  while 
Tens  were  all  anxious  to  make  a  high  score,  all  were  notice- 
ably more  careful  than  the  Sixes,  or  the  average  run  of  the  Eights. 

There  were  varying  degrees  of  interest  on  the  part  of  the 
subjects  in  the  problem  itself,  in  the  subject's  own  progress,  both 
in  respect  to  his  own  record  and  his  relation  to  others.  Sixes 
were  all  working  only  because  they  were  told  to,  and  any  effort 
exerted  was  merely  for  the  sake  of  approbation.  Eights  were 
interested  at  first  and  glad  to  work,  but  toward  the  end  of  the 
time  became  tired  of  the  experiment  and  wanted  to  quit,  or  take 
up  something  new,  yet  when  once  at  work  they  all  seemed  to 
put  forth  considerable,  if  not  maximum,  effort.  One  exception 
to  the  Eights  is  to  be  classed  with  the  Tens.  The  Tens  from 
the  first  were  interested.  There  was  a  high  degree  of  self  rivalry, 
and  of  rivalry  with  each  other.  Each  child  knew  his  score,  and 
remembered  it  to  compare  notes  with  the  others  later.  Among 
the  Ten  boys  this  was  very  pronounced;  so  great  was  their  de- 
sire to  excel  that  all  practiced  the  finger  movement,  whose  se- 
quence they  easily  learned  in  the  first  and  second  day's  work,  and 
when  in  their  playroom  one  used  a  table  top,  two  a  piano,  one 
an  organ,  and  one  drummed  in  the  air.  The  practice  of  the  girls 
was  all  confined  to  work  in  the  laboratory. 


DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE        35 

Only  one  Six  was  able  to  work  with  the  keys  and  small 
colors  concealed.  One  Eight  managed  it  on  the  second  day;  five 
on  the  third ;  one  on  the  fifth ;  one  on  the  sixth,  and  two  not  at 
all,  while  all  of  the  Tens  succeeded  by  the  beginning  of  the 
third  day — five  on  the  first  day,  four  on  the  second  and  one  on 
the  third. 

The  experiment  is  a  valuable  one  for  indicating  the  ability 
of  an  individual  to  comprehend  a  simple  explanation  of  details, 
his  power  of  motor  coordination,  capacity  for  voluntary  effort 
and  sustained  interest.  It  might  be  used  as  a  simple  test  of  in- 
telligence if  ten  trials  were  taken  at  one  sitting.  When  accord- 
ing to  our  results  a  Six  should  comprehend  the  experiment,  be 
able  to  use  two  fingers  and  have  a  record  averaging  about  20 
correct  strokes,  with  a  moderate  increase  in  his  curve  from  first 
to  last.  An  Eight  should  comprehend  that  he  is  to  use  four 
fingers  and  make  some  attempt  to  do  so  and  reach  an  average  of 
about  50  correct  strokes.  A  Ten  should  us«  four  fingers  cor- 
rectly by  the  tenth  trial  and  make  an  average  of  at  least  75  cor- 
rect strokes. 

Experiment  13.     Ink  Blot  Test. 

As  a  study  of  imagination  an  ink  blot  test  was  used,  the 
ink  blots  being  the  first  ten  in  the  series  of  twenty  described  in 
Whipple's  manual  of  Mental  and  Physical  Tests. 

A  card  was  shown  to  a  subject  to  whom  it  was  explained 
that  "This  blot  was  made  by  dropping  a  blot  of  ink  and  smear- 
ing it  around.  What  do  you  think  it  looks  like?  Of  course  it 
is  not  exactly  like  anything,  but  what  does  it  make  you  think 
of?"  After  giving  all  he  could  see  in  one  position,  the  card  was 
changed  until  it  had  been  in  all  four  positions.  Two  minutes 
were  allowed,  but  most  subjects  refused  to  look  longer  than  a 
minute  and  a  half,  and  many  would  use  less  than  one  minute. 
This  was  particularly  true  of  the  Sixes  and  least  true  of  the 
Tens. 

Naturally  the  experiment  does  not  lend  itself  well  to  nu- 
merical classification,  but  we  find,  in  a  rough  way,  that  the  av- 
erage number  of  objects  seen  to  a  card  are : 


36  ORDAHL 

TABLE  XX 

Sixes  Eights  Tens 

1.6  2.8  3.2 

This  shows  an  increasing  superiority  in  wealth  of  imagina- 
tion from  the  lowest  to  the  highest  grade.  Reduced  to  terms  of 
per  cent,  of  difference,  it  stands  : 

Sixes •  • eO 

Eights 87 

Tens I00 

The  Sixes  found  difficulty  in  seeing  a  different  object  in  an 
ink  blot  i*brn  once  it  had  suggested  anything  to  them,  and  no 
matter  in  what  position  this  card  was  turned,  the  picture  was  apt 
to  remain  the  same.  The  blot  was  to  them  not  so  much  a  sugges- 
tion of  an  object  as  an  actual  picture  of  that  object.  To  a  less 
extent  this  tendency  existed  among  the  Eights,  but  was  hardly 
noticeable  in  the  Tens.  An  occasional  Six  enumerated  objects 
which  the  blot  could  not  have  suggested  and  which  they  could 
not  point  out  When  asked  to  do  so.  To  all  children  the  blots 
suggested  mainly  people  and  animals,  but  the  Sixes  only  name 
the  object,  t<he  Eights  add  some  description  and  qualifying  terms, 
while  the  Tens  both  describe  and  attempt  to  interpret  and  give 
a  somewhat  subjective  character  to  their  report.  Thus  a  Six 
would  say:  "That's  a  lady,  here  is  her  shoe  and  here  is  her 
hands."  An  Eight  would  state:  "That  is  a  lady  with  her  hair  all 
tumbling  down,  and  holding  her  foot  in  her  hand,"  while  a  few 
Tens  would  say:  "She  is  all  excited,  and  she  is  kicking  up  her 
feet  and  her  hair  is  tumbling  down  and  she  is  angry."  Tens 
were  the  least  concrete  and  limited  in  their  range  of  objects 
suggested  by  the  pictures,  such  as  "dead  leaves  blowing  across 
a  ravine,"  and  situations  occasionally  being  given  instead  of 
definite  well-known  animals,  persons  or  common  objects.  Eights 
possessed  a  very  little  of  this  tendency,  but  Sixes  none  at  ail- 
Since  the  work  had  to  be  discontinued  before  the  experi- 
ment could  be  carried  further,  the  above  account  is  given  rather 
to  indicate  the  possibilities  of  the  "ink  blot  test"  as  applied  to 
the  feeble-minded  than  as  an  attempt  to  show  anything  con- 
clusive. A  more  careful  study  along  this  line  would  be  well 
worth  while. 


DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE        37 

Experiment  14.     Drawing  Designs  From  Memory  in  Inverted 

Position. 

The  material  used  in  this  experiment  consists  of  twenty 
2  by  2  inch  squares  drawn  on  a  pasteboard  card  3  by  4  inches. 
In  each  square  were  drawn  two  lines  projecting  inward  from 
the  middle  of  the  sides  or  from  the  corners  as  is  shown  in  Plate 
III,  B.  Sheets  of  paper  containing-  twenty  blank  squares 
of  the  same  size  were  supplied.  The  subject  was  pre- 
sented with  the  designs  one  at  a  time  with  the  follow- 
ing instructions:  "Study  this  design  until  you  can  see 
where  these  lines  would  be  if  the  square  were  turned 
around  until  the  bottom  is  where  the  top  is  and  the  top  is 
where  the  bottom  is.  As  soon  as  you  can  see  where  both 
lines  should  be,  and  can  remember,  start  to  draw  them  in  this 
blank  square  and  I  will  take  this  one  away."  It  was  necessary 
to  say  "turn  around,"  otherwise  the  subject  might  conceive  the 
card  as  ''turned  over"  and  would  conceive  it  as  transparent,  and 
draw  the  lines  accordingly.  The  subject  was  allowed  as  much 
time  as  he  needed.  If  attention  appeared  to  wander,  the  experi- 
menter would  say :  "Just  as  soon  as  you  'have  it,  I  will  take  the 
card  away."  Each  subject  was  put  through  the  series  of  twenty 
once  each  day  for  five  successive  days.  The  results  are  given  in 
Table  21.  The  score  is  obtained  by  counting  the  number  of 
lines  correctly  placed.  It  would  therefore  be  possible  to  score 
forty  at  each  trial. 

TABLE  XXI 

Daily  average  of  correct  cases 

12345    Gen.  Av.  A.D. 

Six   0          00000  0 

Bight    1.4        5.4      11.6      10.7      16.0      11.02  9.7 

Tent    13.3      19.7      19.2      22.0      27.6      20.36  8.7 

This  table  shows  the  average  number  of  correct  cases  for 
Eights  to  be  4.56  out  of  a  possible  40,  and  for  Tens  10.18  out  of 
40.  The  score  is  too  low  to  indicate  any  adequate  comprehen- 
sions on  the  part  of  either  the  Eights  or  Tens.  But  the  daily 
averages  show  the  learning  in  both  cases  to  be  rapid-  The 
Eights  rise  from  1.4  on  the  first  day  to  16.0  on  the  fifth  day. 
The  Tens  increase  from  13.3  to  27.6  in  the  same  time.  This  is 


38  ORDAHL 

not  a  large  score,  since  it  is  possible  for  a  subject  to  score  40 
by  the  fifth  trial,  as  was  actually  done  by  two  of  the  Tens,  and 
yet  the  score  together  with  a  constant  intelligent  effort  on  the 
part  of  higher  grades  would  place  the  test  within  the  compre- 
hension of  Eights  and  Tens.  No  norms,  however,  can  be  sug- 
gested, but  it  is  quite  likely  better  results  would  be  obtained  if 
only  ten  designs  were  used  and  the  sittings  continued  over  ten 
days. 

This  experiment  was  calculated  to  be  a  test  of  what  the 
writers  have  termed  manipulation  of  mental  imagery.  The  ex- 
periment has  in  some  means  met  the  purpose  for  which  it  was 
designed.  Visual  imagery  figures  largely  in  this  problem,  but 
motor  imagery,  or  simple  calculation  with  whatever  imagery 
used  may  suffice. 

A  certain  number  of  persons  were  unable  to  tell  how  they 
do  this  experiment ;  they  "just  see  it."  But  among  the  30  feeble- 
minded cases  certain  characteristic  kinds  of  behavior  were  ob- 
served. They  would  seize  upon  one  line,  attempt  to  image  it, 
turn  around  to  the  reversed  position,  become  confused  on  the 
first  turn  and  slip  back  to  try  again.  Or  they  would  succeed  in 
getting  it  to  the  reversed  position,  then  forget  or  be  unable  to 
image  which  way  it  should  slant.  Some  would  succeed  in  get- 
ting one  line  reversed,  but  would  forget  its  position  before  the 
second  line  had  become  located.  Again,  they  might  apparently 
succeed  in  imaging  the  design  reversed  and  then  lose  the  image 
entirely  before  it  could  be  drawn.  Not  a  few  would  go  a  step 
further,  and  lose  only  one  line  in  the  process  of  construction. 
A  few  would  draw  the  lines  not  reversed  but  as  presented.  This 
is  an  interesting  phenomenon  of  confusion  of  imagery.  The  sub- 
ject sees  the  design  reversed  and  then-  reverses  this  image,  and 
consequently  draws  the  design  as  first  presented.  Two  of  the 
subjects,  both  Ten  boys,  succeeded  by  the  end  of  the  fourth  day 
in  making  a  perfect  score.  They  had  discovered  the  principle 
that  the  lines  must  take  opposite  positions.  They  would  take 
one  glance  at  the  design  and  then  draw.  It  appears  they  imaged 
the  design  as  presented,  then  drew  the  lines  according  to  the  prin- 
ciple in  opposite  positions. 


DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE        3Q 

Whatever  the  method  finally  adopted,  the  initial  trials  in- 
volve a  mental  process  of  considerable  complexity.  The  Sixes 
seemed  to  realize  what  was  wanted,  but  were  totally  unable  to 
make  the  essential  mental  change.  The  writer  made  several  in- 
dividual experiments  of  a  simpler  sort,  on  four  different  Sixes. 
^  simple  drawing  of  a  tree  was  presented  upside  down,  with 
the  instructions  to  draw  it  right  side  up.  Invariably  it  would  be 
drawn  with  the  trunk  upright,  but  the  branches  would  slant  down 
at  an  abrupt  angle.  One  case  succeeded  in  drawing  a  boy  with 
his  head  on  the  ground  and  a  crude  body  on  top  of  that,  but  when 
he  came  to  the  legs,  they  were  put  on  the  shoulders  slanting 
down  to  the  ground. 

The  problem  is,  however,  within  the  grasp  of  Eights  and 
Tens,  with  the  advantage  decidedly  'in  favor  of  the  Tens.  Four 
Eights  failed  almost  completely  and  two  Tens  made  very  poor 
records. 

An  attempt  was  made  to  correlate  the  time  required  to  draw 
the  twenty  designs  with  the  accuracy  of  the  drawing,  but  there 
seemed  to  be  no  relation.  Some  seemed  over-cautious  and  would 
take  so  much  time  that  they  became  confused,  others  would  take 
too  little  time  to  make  sure  of  their  imagery.  Another  class  would 
allow  the  attention  to  wander.  The  time  shortened  between 
the  first  and  last  trial  for  those  who  worked  steadily  and  learned 
rapidly.  The  average  time  required  by  the  Eights  was  26.4 
minutes.  This  was  reduced  to  15  minutes  for  the  last  trial. 
The  Tens  have  an  average  time  of  24.5  minutes  which  was  re- 
duced to  13  minutes  in  the  last  trial.  It  is,  however,  questionable 
if  the  time  element  has  any  meaning  for  these  experiments  as 
conducted.  But  from  general  indications,  it  is  probable  that 
the  most  stable  mentality  would  require  the  medium  amount  of 
time. 

Experiment  15.     Comprehension  of  Complex  Directions. 

This  experiment  was  conducted  with  the  expectation  that 
it  would  test  capacity  to  comprehend  and  execute  slightly  com- 
plex directions.  The  material  used  consisted  of  (i)  a  number  of 
squares  one  inch  each  way  with  a  dot  in  the  center  printed  on 


40  ORDAHL 

sheets  of  paper;  (2)  a  number  of  circles  one  inch  in  diameter 
with  a  dot  in  the  center  printed  on  sheets  of  paper;  (3)  a  series 
of  directions,  as  follows. 

A 

1.  Show  me  the  center  of  that  square. 

2.  Show  me  the  middle  of  the  upper  side. 

3.  Show  me  the  lower  left  corner. 

4.  Show  me  the  middle  of  the  right  side. 

5.  Show  me  the  upper  left  corner. 

6.  Show  me  the  middle  of  the  lower  side. 

7.  Show  me  the  upper  right  corner. 

B 

8.  Draw  a  line  from  the  center  of  that  square  to  the  upper 

left  corner. 

9-     Draw  a  line  from  the  center  of  that  square  to  the  mid- 
dle of  the  left  side. 

10.  Draw  a  line  from  the  center  of  that  square  to  the  lower 

right  corner. 

11.  Draw  a  line  from  the  center  of  that  square  to  the  mid- 

dle of  the  upper  side. 

12.  Draw  a  line  from  the  center  of  that  square  to  the  upper 

right  corner. 

13.  Draw  a  line  from  the  center  of  that  square  to  the  middle 

of  the  right  side. 

C 

14.  Draw  a  line  from  the  middle  of  the  right  side  to  the 

upper  left  corner. 

15.  Draw  a  line  from  the  lower  left  corner  to  the  middle  of 

the  upper  side. 

16.  Draw  a  line  from  the  middle  of  the  left  side  to  the  lower 

right  corner. 

17.  Draw  a  line  from  the  upper  right  corner  to  the  middle 

of  the  lower  side. 

18.  Draw  a  line  from  the  middle  of  the  left  side  to  the  mid- 

dle of  the  upper  side. 

19.  Draw  a  line  from  the  middle  of  the  lower  side  to  the 

middle  of  the  right  side. 


DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE        41 

D 

20-     Draw  a  square  on  that  circle  so  that  the  upper  left  cor- 
ner of  the  square  will  be  at  the  center  of  the  circle. 

21.  Draw  a  square  on  that  circle  so  that  the  middle  of  right 

side  of  the  square  will  be  at  the  center  of  the  circle. 

22.  Draw  a  square  on  that  circle  so  that  the  lower  left  cor- 

ner of  the  square  will  be  at  the  center  of  the  circle. 

23.  Draw  a  square  on  that  circle  so  that  middle  of  upper 

side  of  the  square  will  be  at  the  center  of  the  circle. 

24.  Draw  a  square  in  that  circle  so  that  the  upper  right  cor- 

ner will  be  at  the  center  of  the  circle. 

Series  A  was  intended  to  be  preliminary  only,  but  the  Sixes 
found  great  confusion  here.  A  few  succeeded  in  getting  half 
of  the  directions  correctly,  but  even  when  they  could  find  the 
right  point  with  urging,  there  was  no  certainty  they  would  do 
so  again  within  the  next  few  minutes. 

Great  care  was  taken  to  secure  the  utmost  attention  on  the 
part  of  the  subject  while  giving  the  directions.  After  Series  A 
was  completed  no  direction  was  repeated.  Three  trials  were 
given  on  three  successive  days  and  the  average  taken  of  these 
three  trials.  There  was  practically  no  average  to  take  since  the 
subjects  all  stopped  at  the  same  point  each  day.  There  was  no 
evidence  of  learning  for  the  three  trials  given.  The  results  are 
given  in  Table  22. 

TABLE  XXII 
Scries—  A        B        C        D 

Six    0000 

Bight  10       10        4         0 

Ten    10       10         7         4 

Table  22  shows  the  number  of  cases  that  comprehend  and 
execute  the  different  series  of  commands.  All  of  the  Eights 
and  Tens  pass  Series  A  and  B,  four  Eights  pass  C  and  none  of  the 
Eights  pass  D.  Six  Tens  pass  C  and  four  Tens  pass  all  four 
series. 

A  common  error  in  Series  C,  the  one  made  by  six  Eights 
and  three  Tens,  was  always  to  draw  the  line  through  the  center 
of  the  square,  no  matter  from  what  point  the  line  started  or 
terminated.  For  example,  if  the  direction  was  No-  19,  "Draw  a 


42  ORDAHL 

line  from  the  middle  of  the  lower  side  to  the  middle  of  the  right 
side,"  the  subject  would  draw  his  line  to  the  center,  then  to 
the  middle  of  the  right  side.  This  may  have  been  because  of  a 
habit  established  in  executing-  the  commands  of  Series  B,  but 
even  so,  it  is  an  error  caused  through  superficial  attention  and 
inability  to  control  more  than  one  idea  at  a  time. 

The  errors  made  in  Series  D  were  various.  The  character- 
istic mistake  was  to  interchange  the  part  of  the  square  mentioned 
with  the  part  of  the  circle,  e.  g.,  for  direction  No.  20,  "Draw  a 
square  on  that  circle  so  that  the  upper  left  hand  corner  of  the 
square  will  be  at  the  center  of  the  circle,"  the  subject  would  draw 
a  small  square  in  the  upper  left  portion  of  the  circle. 

The  experiment  does  not  at  first  notice  appear  to  be  diffi- 
cult, but  it  is  probably  the  best  test  of  the  fifteen  for  the  control 
of  ideas,  and  comes  more  nearly  to  being  an  elementary  test  in 
the  higher  thought  processes.  The  errors  made  already  indi- 
cate the  difficulty  the  Tens  had  in  keeping  ideas  distinct  and 
clearly  in  mind  when  there  is  more  than  one.  It  also  indicates 
a  looseness  of  association,  and  reveals  likewise  an  indisposition 
to  mental  effort,  and  a  tendency  to  be  satisfied  with  superficial 
observation  and  any  kind  of  an  execution.  On  the  other  hand, 
the  fact  that  four  typically  feeble-minded  children  of  the  mental 
age  Ten  can  comprehend  the  directions  and  make  the  executions 
readily,  indicates  a  certain  individual  difference  in  the  higher 
thought  processes  of  the  feeble-minded.  It  is  quite  possible  that 
persons  may  be  capable  of  exercising  a  relatively  high  degree  of 
control  of  the  associative  process  and  yet  be  sufficiently  defective 
in  other  ways  to  make  him  feeble-minded. 

In  summarizing  the  per  cent,  difference  between  the  age 
levels  for  the  fifteen  experiments,  we  find  in  Table  23,  that  the 
Tens  are  100  per  cent.,  the  Eights  74  per  cent,  and  the  Sixes  29 
per  cent.  Since  one  experiment  is  not  directly  comparable  with 
another  in  numerical  terms,  their  averages  are  not  an  absolute 
measure,  but  from  all  evidence  they  are  a  reasonable  indication  of 
the  psychological  difference  between  the  mental  levels  studied. 


DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE 


43 


TABLE  XXIII 

Experiment  Ten  Eight  Six 

1             100  98  84 

100  36  24 

3              100  85  28 

4 100  89  82 

100  84  45 

6              100  86  07 

7 100  90  45 

8              100  78  20 

9              100  77  07 

10             100  71  21 

11              100  68  21 

12             100  36  13 

13 100  87  50 

14             100  54  0 

15             100  78  0 

Average    100        74        29 

If  the  experiments  are  grouped  according  to  the  main  psy- 
chological process  involved,  the  various  levels  are  related  as  in- 
dicated under  the  following  'heads. 

TABLE  XXIV 

Ten    Eight    Six 

Sensory  Discrimination   (Experiments  2  and  6)    100 

Attention    (Experiments   5,   3,   4.   1)    100 

Memory   (Experiment  11)    100 

Learning  (Experiment  12)    100 

Judgment  (Experiment  7,  8,  9,  10)   100 

Imagination  (Experiment  13)    100 

Reasoning  (Experiment  14,  15)    100 

This  grouping  has  seemed  justified  from  what  could  be 
learned  in  observation  of  the  subjects  at  work.  Each  experi- 
ment involves  a  varying  degree  of  complexity,  but  for  the  sub- 
jects of  this  experiment  the  above  named  processes  seem  to  be 
the  chief  ones  involved. 

In  all  experiments  attention  is  involved  and  it  is  probable 
that  this  is  the  psychological  process  in  which  the  levels  of  in- 
tejligence  differ.  The  Sixes  seem  to  have  a  consciousness  quali- 
tatively different  from  Eights  and  Tens-  It  may  be  character- 
ized as  an  inconsistent  shifting  blur.  Sensory  discrimination  is 
low  for  this  reason.  For  this  same  reason  memory  is  feeble  and 
association  irrelevant.  Learning  is  a  slow  process  and  because 


44  ORDAHL 

of  their  wavering  attention  and  inability  to  perceive  essential  dif- 
ferences, their  judgment  is  defective,  and  their  imagery  indefin- 
ite and  limited.  They  are  practically  unable  to  perform  the  sim- 
plest problem  involving  reasoning.  The  zero  score  in  the  last 
column  holds  true  for  all  experiments  where  reasoning  is  in- 
volved. 

There  is  sufficient  difference  between  the  score  of  Eights 
and  Tens  to  indicate  that  the  Eights  differ  likewise  in  a  qualita- 
tive way  from  the  Tens,  but  it  is  not  so  apparent  from  their  gen- 
eral behavior  in  the  laboratory.  They  fall  behind  the  Tens  in 
every  case  involving  a  complex  situation,  or  where  two  or  three 
ideas  are  concerned,  thus  indicating  a  difference  in  power  of  per- 
ceiving relations  and  making  logical  associations.  Indications 
are  that  the  Eights  would  have  appeared  different  from  the  Tens 
qualitatively  in  making  relevant  associations,  could  further  ex- 
periments have  been  made  involving  higher  thought  processes. 
The  Tens  are  superior  in  every  process  involved  in  the  fifteen 

experiments,  but  they  fall  short  of  normal  in  purpose,  genuine 
interest  and  ability  to  see  the  meaning  of  things. 
Sex  Differences. 

Data  as  to  sex  differences  are,  of  course,  only  of  general  value 
in  this  experiment  owing  to  the  limited  number  of  cases  chosen. 
However,  the  results  for  the  different  sexes  are  given,  because  of 
what  they  show  in  regard  to  the  children  studied.  In  comparing 
the  sex  differences,  the  relationship  was  reduced  to  a  percental 
basis  in  each  experiment,  and  each  age,  by  considering  the  actual 
score  of  the  higher  ranking  sex  as  100  and  dividing  the  lower 
score  by  this  to  get  its  per  cent.  Thus,  in  memory  with  imme- 
diate recall  the  Ten  girls  scored  68,  the  Ten  boys  87.  Hence, 
the  boys  were  valued  100  per  cent,  and  the  girl  78.  In  experi- 
ments u,  14  and  15,  the  Sixes  did  practically  nothing,  and  hence 
are  not  considered  in  the  comparison,  but  are  valued  at  zero. 


DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE        45 
TABLE  XXV 


Sis 

Eight 

Ten 

Sex  Superiority 

Girls 

Boys 

Girls 

Boys 

Girls 

Boys 

Six 

Eight 

Ten 

1. 

Strength  of  grip    

.     88 

100 

80 

100 

79 

100 

B 

B 

B 

2. 

Judgment  of  movement 

100 

79 

100 

66 

100 

94 

G 

G 

G 

3. 

Simple  reaction  time.. 

66 

100 

100 

89 

89 

100 

B 

G 

B 

4. 

Tapping  test   

73 

100 

85 

100 

98 

100 

B 

B 

B 

5. 

Attention   span  A    .... 

100 

74 

100 

99 

79 

100 

G 

G 

B 

Attention    span    B  

100 

82 

100 

74 

90 

100 

G 

G 

B 

Attention    span    C  

100 

80 

100 

80 

70 

100 

G 

G 

B 

6. 

Discrimination  ofigrays 

92 

100 

93 

100 

100 

83 

B 

B 

G 

7. 

Judgment  of  forms, 

two   dimensions    

86 

100 

100 

100 

65 

100 

B 

O 

B 

8. 

Judgment  of  form.... 

96 

100 

79 

100 

10 

100 

B 

B 

B 

9. 

Judgment  of  size  

77 

100 

100 

85 

100 

86 

B 

G 

G 

10. 

Judgment  of  forms. 

three  dimensions   .  .  . 

.     77 

100 

69 

100 

10 

100 

B 

B 

B 

11. 

Memory  of  geometrical 

forms: 

Immediate     

0 

0 

100 

95 

78 

100 

G 

B 

10-second    

0 

0 

100 

95 

90 

100 

G 

B 

1-minute    

0 

0 

100 

97 

81 

100 

G 

B 

12. 

Modified   typewriting.  . 

100 

91 

100 

91 

67 

100 

G 

G 

B 

13. 

Ink  blot  test  

77 

100 

100 

91 

64 

100 

B 

G 

B 

14. 

Drawing   designs    in- 

verted   

0 

0 

100 

84 

46 

100 

G 

B 

15. 

Comprehension  of  di- 

rection     

0 

0 

85 

100 

100 

100 

B 

Average  88         93         94          84         62         98 

Table  25  given  the  relative  difference  for  each  age  and 
experiment.  Under  the  columns  headed  "sex  superiority" 
are  given  letters  "B"  and  "G"  indicating  whether  the  boys  or 
girls  are  superior  for  that  age  and  experiment.  Here  we  see 
that  on  the  average  for  the  Sixes  and  Tens  the  boys  rank  higher, 
and  for  the  Eights  the  girls  rank  higher-  The  greater  superiority 
of  the  Ten  boys  is  partly  due  to  the  fact  that  the  boys  average 
a  little  higher  according  to  the  scale  of  intelligence  than  the  Ten 
girls,  and  that  one  of  the  Ten  girls  was  handicapped  by  a  visual 
defect.  Further  than  this  there  seems  to  be  no  explanation  for 
the  sex  differences. 

Individual  Variations.  » 

In  many  of  the  experiments  there  were  individuals  of  one 
mental  age  whose  results  resembled  more  nearly  those  of  the 
higher  or  lower  group.  For  example,  if  the  averages  of  the  thirty 
individuals  are  arranged  in  order  of  rank  with  respect  to  the 
others  in  that  experiment,  one  of  the  Sixes  ranked  up  somewhere 
between  the  tenth  and  twentieth,  two  of  the  Eights  around 


46  ORDAHL 

twenty-second  or  twenty-third,  and  two  of  the  Tens  down  among 
the  second  ten  subjects.  But  it  was  the  same  individuals  who 
ranked  above  or  below  the  others  of  his  mental  age.  One  su- 
perior Six  was  a  girl  of  exceptionally  good  physical  endowment, 
who  had  the  advantage  of  a  naturally  good  motor  co-ordination 
and  freedom  from  physical  fatigue.  One  of  the  Eights  who 
out-ranked  her  fellows  was  also  thus  favored  physically,  besides 
being  interested  in  the  tasks  and  having  an  eagerness  to  succeed 
which  made  her  put  forth  her  best  efforts.  The  other  Eight  who 
excelled  was  infinitely  patient,  and  made  up  in  effort  and  pains 
for  what  he  lacked  in  intelligence.  The  two  Tens  who  fall  be- 
low do  so  because  of  an  indisposition  to  try,  and  in  the  case  of 
one  an  eye  defect  which  hindered  in  some  experiments.  One  was 
indifferent  and  careless,  and  the  other  sometimes  hostile  to  the 
work,  but  when  they  could  be  induced  to  put  forth  effort  they 
ranked  well  up  among  the  Tens.  Despite  these  variations  it  is 
interesting  to  note  that  in  the  experiments  of  a  more  difficult 
character  involving  more  complex  mental  processes,  such  as 
the  comprehension  of  directions,  drawing  reversed  designs,  and 
memory,  the  classes  are  distinct  and  separate,  with  no  over- 
lapping. 

Summary  and  Conclusions. 

Certain  general  facts  stand  out  in  regard  to  the  findings  of 
the  different  experiments.  Experiment  I  shows  that  in  strength 
of  grip  the  feeble-minded  children,  while  physically  they  may 
be  as  strong  as  the  average  normal  individuals  of  the  same  age, 
fall  below  because  of  inability  to  make  the  voluntary  effort 
necessary  to  produce  their  best  results.  Feeble-minded  children 
show  a  decided  difference  in  the  results  for  the  two  hands,  and 
are  therefore  not  ambidextrous  as  has  often  been  supposed. 
There  is  a  slight  difference  in  the  three  mental  ages,  Sixes  .rank- 
ing lowest  and  Tens  highest. 

Experiment  2  shows  that  in  a  test  so  simple  as  judgment 
of  extent  of  'movement  there  is  little  difference  in  the  three  men- 
tal levels,  the  superiority  of  the  Tens  over  the  Eights  and  the 
Eights  over  the  Sixes  being  due  rather  to  more  intelligent  be- 


DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE        47 

havior  in  following  the  instructions  of  the  experiment  on  the 
part  of  the  upper  grades  of  intelligence. 

Experiment  3  shows  that  a  simple  reaction  experiment  is, 
for  the  feeble-minded,  more  than  a  simple  voluntary  process; 
what  would  be  marginal  or  reflex  for  normal  subjects  are  for 
these  distinctly  conscious  processes,  so  that  reacting  to  a  stim- 
ulus involves  holding  several  factors  in  consciousness  before  re- 
acting to  them.  The  lower  the  mental  level  the  more  this  is  true 
and  the  harder  the  task  is. 

In  Experiment  4,  the  curve  of  tapping  shows  the  greatest 
lack  of  voluntary  effort  on  the  part  of  the  Sixes,  and  least  on  the 
part  of  the  Tens,  who  are  still  slower  and  show  a  different  curve 
from  what  we  would  expect  for  normals.  Pounding  the  key  and 
waste  of  energy  by  the  Sixes  evidences  their  lack  of  judgment- 
Experiment  5,  which  is  a  real  attention  experiment,  shows 
more  difference  in  the  results  of  the  three  levels,  the  score  be- 
ing proportional  to  the  mental  age,  and  the  more  complex  the 
series,  the  greater  the  difference  in  the  results  of  the  three 
groups.  Here  we  find  a  difference  in  the  power  of  comprehend- 
ing the  demands  of  the  problem  and  adjusting  to  them,  and  a 
difference  in  attention  span  varying  directly  with  the  mental 
age,  the  Sixes  being  the  weakest. 

Experiment  6,  discrimination  of  grays,  seems  to  indicate  that 
as  far  as  brightness  discrimination  itself  is  concerned  the  three 
levels  are  about  equal,  the  differences  that  the  results  show  being 
due  to  the  fact  that  the  lower  levels  are  sometimes  careless  in 
making  their  decisions.  Any  variation  is  rather  a  matter  of  at- 
tention than  of  discriminibility. 

Experiments  7  and  8  show  that  an  experiment  should  be  dif- 
ficult enough  to  require  some  effort  on  the  part  of  feeble-minded 
subjects,  for  they  are  too  easily  satisfied  with  moderate  success; 
if  they  get  things  "almost  right,"  they  cease  to  try  when  per- 
fection would  be  possible  with  a  little  extra  effort.  Experiment 
8  was  too  difficult  for  the  Sixes  because  there  was  too  much  to 
hold  in  consciousness  at  once  and  too  much  sustained  attention 
demanded.  Experiment  9,  the  judgment  of  size  and  form,  is  not 
an  immediate  process.  It  is  an  association  of  imagery  of  different 


48  ORDAHL 

sense  realms,  which  is  not  spontaneous,  but  constructive,  and 
involves  some  reasoning.  Hence  the  greater  difficulty  for  the 
lower  levels  of  intelligence. 

Experiment  10  on  the  judgment  of  forms  of  three  dimensions 
is  a  better  test  for  comparing  the  three  levels  of  intelligence  than 
the  preceding  tests  because  of  its  complexity.  It  is  a  severe 
task  for  the  Sixes,  easier  for  the  Eights  and  least  difficult  for 
Tens- 
Experiment  II  on  the  memory  of  complex  geometrical  forms 
involves  so  much  discrimination  of  difference  in  form  and  so  much 
attention  that  it  is  more  than  a  test  of  retentiveness.  In  fact,  it 
is  difficult  to  determine  in  how  far  demands  made  on  these  higher 
mental  processes  hinder  it  from  being  a  memory  experiment  for 
the  Sixes,  for  the  distinguishing  of  the  forms  themselves  is  an 
almost  impossible  task. 

Experiment  12  on  the  modified  typewriting  varies  in  diffi- 
culty with  the  different  mental  ages,  both  as  to  speed,  accuracy, 
and  rate  of  learning.  This  difference  was  due  to  the  greater 
unity  of  consciousness  of  the  higher  levels,  since  for  them  some 
factors  were  from  the  start  marginal,  while  for  a  Six,  and  to  a 
lesser  degree  for  an  Eight,  all  factors  were  apt  to  be  of  equal  value 
in  consciousness,  with  a  resulting  confusion.  Rivalry  was  char- 
acteristic of  the  Tens,  Eights  showed  little  rivalry,  but  a  pleas- 
ure in  a  good  record,  wliile  Sixes  worked  because  they  had  to, 
but  enjoyed  the  approbation  of  the  experimenter. 

Experiment  13,  the  ink  blot  test,  gave  higher  results  in  pro- 
portion to  the  height  in  intelligence.  This  is  due  to  the  greater 
wealth  of  imagery  the  brighter  subjects  possessed,  owing  to  their 
capacity  for  taking  in  more  ideas  with  a  resulting  richer  mental 
content  than  lower  grades. 

Experiment  14,  on  comprehending  directions,  shows  a  de- 
cided lack  of  reasoning  ability  on  the  part  of  the  Sixes.  They 
have  difficulty  in  holding  details  in  mind  long  enough  to  relate 
and  compare  them.  It  means  a  degree  and  duration  of  atten- 
tion and  voluntary  effort  not  possible  for  the  Sixes,  difficult  for 
Eights,  but  relatively  easy  for  the  Tens. 


DIFFERENCES  BETWEEN  LEVELS  OF  INTELLIGENCE        49 

In  general,  results  of  the  above  experiments  and  impressions 
made  during  the  study  show  the  following. 

(r)  There  is  a  noticeable  lack  of  energy  and  capacity  for 
voluntary  effort  on  the  part  of  the  feeble-minded,  and  Sixes  stand 
the  lowest,  Eights  next  and  Tens  highest  among  the  subjects  in 
question. 

(2)  All  are  weak  in  degree,  duration  and  span  of  attention, 
the  Sixes  being  lowest  and  Tens  highest.     So  characteristic  is 
this  feebleness  of  attention,  that  experiments  dealing  with  other 
mental  processes  are  difficult  to  interpret,  since  every  task  re- 
quires more  or  less  concentration. 

(3)  Probably  all  ages  would  be  equal  in  sensory  discrim- 
ination, if  the  factors  of  attention  and  voluntary  effort  could  be 
eliminated,  but  since  the  simplest  sensory  experiment  involves  at- 
tention, it  is  doubtful  whether  the  feeble-minded  can  be  justly 
compared  as  to  these  simple  processes. 

(4)  The  lower  the  feeble-minded  person  in  the  scale  of 
intelligence  the  less  unified  his  consciousness.      There  do  not 
seem  to  be  two  levels  of  attention  where  one  group  of  percep- 
tions is  in  the  focus  and  the  rest  in  the  margin,  but  all  factors  in 
consciousness  seem  to  be  of  about  uniform  importance.    This  lack 
of  unity  makes  it  difficult  for  the  feeble-minded  to  perceive  the 
real  meaning  of  a  life  situation  and  leaves  him  without  sufficient 
stability  of  purpose  to  direct  his  own  activities. 

(5)  The  three  levels  of  intelligence  differed  as  to  their  emo- 
tional attitude  toward  the  experiments.    A  Six  was  capable  of 
amusement,  but  had  no  genuine  interest  in  the  work.    There  was 
no  desire  to  succeed  other  than  that  provoked  by  the  pleasure 
of  approbation  by  the  experimenter.    An  Eight  took  pleasure  in 
the  actual  performance  of  the  work,  but  not  from  any  personal 
or  social  interest.    A  Ten  showed  general  interest  in  his  success, 
wished  social  approval  and  was  actuated  by  the  spirit  of  rivalry. 

(6)  Lower  grades  are  more  pronounced  in  their  inability  to 
comprehend  directions  and  to  hold  them  in  mind  long  enough  to 
act  on  them;  also  in  their  difficulty  of  adjusting  themselves  to 
the  conditions  of  an  imposed  task.     Eights  suffer  less  from  this 
inferiority  and  Tens  least. 


50  ORDAHL 

(7)  The  lower  the  level  of  intelligence,  the  more  the  sub- 
ject is  lacking  in  reasonableness  and  good  judgment  in  perform- 
ing his  work. 

(8)  The  feeble-minded  have  pronounced  individuality,  but 
are  deficient  in  personality ;  that  is,  their  individual  characteris- 
tics are  very  pronounced,  but  their  traits  and  peculiarities  are  not 
closely  unified  into  a  personality.    A  Six  hardly  regards  himself 
as  an  individual,  an  Eight  makes  superficial  personal  distinctions, 
while  even  for  a  Ten  self-realization  does  not  become  a  reality. 


THE  LIBRARY 
UNIVERSITY  OF  CALIFORNIA 

Santa  Barbara 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW. 


Series  9482 


A       f\  /%  "'''  ''ill  111 


